Benzyl 1,2,3,4-tetrahydrocarbazole-3 or 4-carboxylates

ABSTRACT

NOVEL 9-AROYL-1,2,3,4-TETRAHYDROCARBAZOLES BEARING A CARBOXY SUBSTITUENT AT POSITION 3 OR 4 AND CORRESPONDING ESTERS HAVING ANTIINFLAMMATORY ACTIVITY, THE PREPARATION THEREOF AND NOVEL INTERMEDIATES THEREFOR ARE DESCRIBED.

United States Patent 3,758,496 BENZYL 1,2,3,4-TETRAHYDROCARBAZOLE-3 0R 4-CARBOXYLATES Ernest John Alexander, East Greenbush, and Aram Mooradian, Schodack, N.Y., assignors to Sterling Drug Inc., New York, N. No Drawing. Continuation-impart of application Ser. No. 42,620, June 2, 1970, now Patent No. 3,687,969. This application Nov. 18, 1971, Ser. No. 200,205

Int. Cl. C07d 27 /6'8 U.S. Cl. 260315 36 Claims ABSTRACT OF THE DISCLOSURE Novel 9-aroyl-1,2,3,4-tetrahydrocarbazoles bearing a carboxy substituent at position 3 or 4 and corresponding esters having antiinfiammatory activity, the preparation thereof and novel intermediates therefor are described.

wherein (Ar) represents a benzene ring or a naphthalene ring; Q and Q represent substituents selected from loweralkyl, phenyl-lower-alkyl, lower-alkoxy, phenyl-loweralkoxy, phenoxy, phenyl, di(lower-alkyDamino, loweralkanoylamino, trihalornethyl, trihalornethoxy, halo and hydroxy, where phenyl is unsubstituted'or substituted by from one to three. of the same or: different substituents selected from lower-alkyl, lower-alkoxy, trihalornethyl and halo; Z and Z represent substituents selected from loweralkylthio, lower-alkylsulfinyl, lower-'alkylsulfonyl, amino, and nitro; m represents aninteger from O 'to' (3 n) inclusive; p represents an integer from.0 to (3 -g)' inclu} sive; n and grepresents integers from O to '1 inclusive;

R represents hydrogen, lower-alkyl, 4-acetarhidophe'nyl, lower-alkanoyloxymethyl, benzoyloxymethyl or benzoyloxymethyl substituted on phenyl by. from one to two'of the same or difierent substituents selected from lower alkyl, lower-alkoxy, trihalomethyl, nitro and halo; and

R and R each represent hydrogen or methylpat least one of which is hydrogen; or (Q), taken together with (Z),,, or (Q taken. together with (Z represent methylenedioxy attached to adjacent carbonatoms 3,758,496 Patented Sept. 11, 1973 Ice ' In another aspect of this invention there are provided compounds having the formula wherein (Ar) represents a benzene ring or a naphthalene ring; Q and Q represent substituents selected from loweralkyl, phenyl-lower-alkyl, lower-alkoxy, phenyl-loweralkoxy, phenoxy, phenyl, di(lower-alkyDamino, trihalomethyl, trihalomethoxy, halo and hydroxy, where phenyl is unsubstituted or substituted by from one to three of the same or difierent substituents selected from lower-alkyl, lower-alkoxy, trihalomethyl and halo; Z and Z represent lower-alkylthio; m represents an integer from 0 to (3n) inclusive; p represents an integer from 0 to (3g) inclusive; n and g represent integers from 0 to 1 inclusive; R vrepresents hydrogen, lower-alkyl, 4-acetamidophenyl, lower-alkanoyloxymethyl, benzoyloxymethyl or benzoyloxymethyl substituted on phenyl by from one to two of the same or difierent substituents selected from loweralkyl, lower-alkoxy, trihalomethyl, nitro and halo; and R represents hydrogen or methyl; or (Q taken together with (2 or (Q taken together with (Z5); represent methylenedioxy attached to adjacent carbon atoms. V a .7

It will be understood, here and throughout the specification, that when R represents methyl, said methyl can occur at any one of the positions C C C or C of the 1,2,3,4-tetrahydrocarbazole ring.

In anotheraspect of the invention there are provided compounds having the formula CO H (QM coat III whereiri (Ar) represents a benzene ring or a'na'phthaleiie ring; Q'arid Q represent members of the group consisting of 'lower-al'lryl, phenyl-lower-alkyl, 1ower-alkoxy,phenyllower alko'iry, phenoxy, phenyl, amino, di(lower-alkyl) amino, lower-alkanoylamino, trihalomethyl, trihalomethoxy, haldand hydroxy; Z and Z represent members of thegro'up consisting of lower-alkylthio, lower-alkylsulfinyl, lower-alkylsulfonyl and nitro; m represents an integer frornp" o(3.r'n) inclusive; p represents an integer from Qjto (3 --g) jinclusive; and n and g represent integers from ,O 1Q 1 iI;l1 liSiYe;-0l' (Q) taken together'with (Z),,, or jQi) takeri together with (Z represent methylenedioxy attached to adjacent carbon atoms.

f'orisubstituted by ff'rom one to three of thesa In another aspect of the invention there aresprovided compounds having the formula (IV) wherein R represents hydrogenor (Ar) represents a benzene ring or a naphthalene ring; Q and Q represent substituents selected from loweralkyl, phenyl-lower-alkyl, lower-al-koxy, phenyl-loweralkoxy, phenoxy, phenyl, di(lower-alkyl)amino, trihalomethyl, t-rihalomethoxy and halo, where phenyl is unsubstituted or substituted by from one to three of the same or difierent substituents selected from lower-alkyl, lower-alkoxy, trihalomethyl and halo; Z and Z represent lower-alkylthio; m represents an integer from O to (3n) inclusive; p represents an integer from 0 to (3-g) inclusive; n and g represent integers from 0 to l inclusive; (Ph) represents a benzene ring; Q represents a substituent selected'from lower-al'kyl, lower-alkoxy and halo; r

represents a'n integer from 0 to 3 inclusive; Z represents hydrogen; and R and R each represent hydrogen or methyl, atleast one of which is hydrogen; or (Q 'takentogether with (2 or (Q taken together with (Z or (Q taken together with Z represent methyl enedioxy attached to adjacent carbon atoms.

The compounds of the invention havingForrnulas I and II were found to have antiinflammatoryaetivitywhen tested in rats according to the pharmacological'test'pr cedures more fully described hereinbelow and are indicated for use as antiinflammatory agents. f I

The compounds having Formulas III and IVabove are useful as intermediates in the preparation" of "the "compounds of Formula I above as more fully described he'reh In another aspect of the invention there are provided wherein R representshydfog en or (Ar) represents a benzene ring or a naphthalene ring; Q

,and Q represent substituents selected from lOwer-alkyl, phenyl-lower-alkyl, lower-alkoxy, ,phenyl-lower-alkoxy,

pheno'xy," .fphenyl di(lower-alkyl)amino, trihal'orne'thyl, ,trihalornethoxy and h 'alo,'., where phenylis unsubstituted drainersubstituents selected from lower-alkylg \gver-alkoxy alo'r'ne'thyl and halo; Z and Z representlowenalkylrepresents, an integer from'O to (3-31) inclusive;

pfreprese'nts an integer from O'to (3-g) inclusive; n' and 'grepresent integers from O to l inclusive; (Ph) represents a benzene ring; Q represents a substituent selected from lower-alkyl, lower-alkoxy 'and halo; r represents 'an integer from 0 to 3" inclusive; Z represents hydrogen; and R represents hydrogen or'methyl; or (Q taken together carbon atom and methylene carbon atom (CH respectively and it will be further understood that the substituents represented by Q Q Q Z, Z Z and Z Q1 Q3, Q5 Q8 Z1 3 5 and 8; and Q6 and Q9 can occur at any of the available positions of the benzene ring of the tetrahydrocarbazole; the benzene ring or naphthalene ring of the radical represented by (Ar); and the benzene ring of the radical represented by (Ph) respectively and where, in each case, there is more than one substituent they can be the same or different and they can occur in any position combination relative to each other. n

It will also be understood, here and throughout the specification, that when (Q) taken together with (2) (Q taken together with (Z (Q taken together with (Z (Q taken together with (Z (Q taken 'the rings represented by (Ar)- and (PM to which it is attached, and it will be further understood that for any particular compound of the invention, either or both of (Q) "taken together with- (Z) and (Q taken together with (Z (Formulas I and III), or (Q taken together with (2 and (Q taken together with (Z (Formula II), or one or two or all of- (Q4) taken together with (Z (Q taken together with (Z and (Q taken together with Z (Formula IV), or (Q taken together with (Z (Q taken' together with (Z and (Q taken together with Z (Formula V) can be methylenedioxy attached to adjacent carbon atoms.

As used throughout this specification, the terms loweralkyl, lower-alkoxy, and lower-alkanoyl mean such groups preferably containing from one to six carbon atoms which can be arranged as straight or branched chains, and, without limiting the generality of the foregoing, are illustrated. by methyl, ethyl, propyl, isopropyl, butyl, secbiityl, amyl, hexyl and the like for alkyl; methoxy, ethoxy,

propoxy, isobutoxy, hexylo'xy and'the like for alkoxy;

and acetyl, 'propionyl, butyryl, isobutyryl, hexanoyl and the like for alkanoyl.

-A s used throughout this specification the term halo means chloro, bromo, iodoand fluoro.

' The free acid forms of the compounds'of Formulas I and IIwhere R and R respectively are hydrogen are convertible to the corresponding salt form by interaction of a particular acid with a base, and such salts are considered to be the full equivalents of theacids and esters of Formulas I and II. Examples of such salts are salts of heavy metals such as zinc and iron, alkali metal salts,

for 'examplersodium and potassium; alkali earthmetal salts, for example, calcium and barium; the aluminum and magnesium" salts; and ammonium salts, such as those derived from ammonia or amines such as methylamine, ethylamine, isopr'opylramine, hexylarnine, dimethylamlne,

die'thylarnine, methyl ethylamine, di(se'c-propyl)amine, di-

amine and the like. Of course, by'virtue of the herein disclosed pharmaceutical utility of the compounds of Formulas I and II the preferred salts are the pharmaceutically acceptable salts and such salts are considered to be the full equivalents, particularly for pharmaceutical use, of the free acids and esters of Formulas I and II.

In the process aspects of the invention there are provided the processes described more fully hereinbelow as follows:

The compounds of the invention having Formula I are prepared by the methods described and illustrated in the flow charts below.

They are prepared by one method by reacting an appropriate l-aroyl-l-phenylhydrazine (Formula VI) or the corresponding aldehyde l-aroyl-l-phenylhydrazone, e.g., acetaldehyde or benzaldehyde hydrazone, with an appropriate cyclohexanone-4-carboxylic acid or ester thereof- (Formula VII) or the known cyclohexanone-4,4-dicarboxylic acid (Formula VIIa) to give the corresponding 1,2,3,4-tetrahydrocarbazole 3 carboxylic acid or ester thereof (Formula I) or corresponding 1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid (Formula III) respectively and further reacting the dicarboxylic acid (III), under pyrolytic conditions, in order to effect mono-decarboxylation to give the corresponding compound of Formula I (R=H). The condensation reaction is carried out in a suitable solvent, for example acetic acid or, when the corresponding lower-alkyl ester is desired, in, an alkanol such as methyl alcohol, ethyl alcohol, isopropyl alcohol or butyl alcohol in the presence of a suitable condensing agent, for example, acids such as hydrochloric, hydrobromic, polyphosphoric, sulfuric and acetic acid, and Lewis acids such as zinc chloride, cuprous chloride, boron trifluoride, boron trifluoride etherate and the like.

VIIa

The reaction of the hydrazines, or corresponding acid-addition salt, having Formula VI or corresponding aldehyde l-aroyl-l-phenylhydrazones with the cyclohexanones having Formulas VII and VIIa can be carried out in a suitable solvent at temperatures of from about C. to about 125 C. for from about fifteen minutes to several hours, the choice of solvent, catalyst, temperature and time of reaction depending on the nature of the reactants. If an acid-addition salt of the l-aroyl-I-phenylhydrazines is employed, an additional condensing agent is not necessary. Generally, the reaction is conveniently carried out by heating a solution of an appropriate l-aroyl-1-phenylhydrazine of Formula VI in the form of its acid-addition salt, e.g. hydrochloride salt, and an appropriate cyclovhexanone of Formula VII or VIIa in glacial acetic acid at about 60 to 70 C. for about thirty minutes. In the 'case of the aldehyde l-aroyl-l-phenylhydrazones, the reaction is conveniently carried out by heating under reflux a solution of the appropriate benzaldehyde or acetaldehyde l-aroyl-l-phenylhydrazone and an appropriate cyclohexanone of Formula VII (Where R=hydrogen or lower-alkyl) or VIIa in glacial acetic acid at from 90 C. to reflux temperature in the presence of an excess of hydrochloric acid or sulfuric acid for one to six hours;

the acid condensing agent can be added initially or subsequent to the heating of the solution of the reactants until liberation of a stoichiometric amount of aldehyde so formed is complete. The mono-decarboxylation reaction leading to the compounds of Formula I where R is hydrogen can be carried out by heating the appropriate dicarboxylic acid having Formula III, if desired in the presence of a suitable solvent, to a temperature where carbon dioxide evolution begins and continuing heating at about that temperature until carbon dioxide evolution ceases. Generally the reaction proceeds readily when an appropriate dicarboxylic acid of Formula III is heated, in the absence of solvent, at about 170 to 200 C.

The compounds of the invention having Formula I where R is lower-alkyl can also be prepared from the free carboxylic acids (I, R=H) by standard esterification procedures. In view of the sensitivity to hydrolysis of the 9- aroyl moiety of the compounds having Formula I to the strong acidic conditions used in some procedures to effect esterification, for example, treatment with alkanols in the presence of a strong acid, esterification procedures which avoid such conditions are preferred, for example, esterification with diazoalkanes or with alkanols (ROH, where R is lower-alkyl) in the presence of an equivalent of cyclohexylcarbodiimide. Alternatively the free carboxylic acid (I, R=H) can be converted to the acid chloride or bromide, using standard procedures, e.g., reaction with thionyl chloride or bromide, followed by treatment with an appropriate alcohol (ROH, where R is lower-alkyl or 4-acetamidophenyl). The carboxylic acid esters (I, R=alkanoyloxymethyl or unsubstituted or substituted benzoyloxymethyl) are prepared by reacting the free carboxylic acid (I, R=H) with the appropriate chloromethyl alkanoate or an appropriate chloromethyl benzoate in a suitable solvent, e.g., dry dimethylformamide, in the presence of a suitable acid acceptor, e.g., sodium or potassium carbonate or sodium or potassium bicarbonate. The chloromethyl alkanoates and benzoates belong to a wellknown class of compounds and are readily prepared by a known procedure, i.e., reaction of the corresponding alkanoic acid chlorides or bromides and benzoic acid chlorides or bromides with paraformaldehyde generally in the presence of a small amount of dry zinc chloride.

.The intermediate l-aroyl-l-phenylhydrazines having Formula VI and corresponding aldehyde l-aroyl-lphenylhydrazones used in the preparation of the compounds having Formula I and III are known compounds or are readily prepared by standard procedures from the corresponding phenylhydrazines and corresponding aroyl halide as follows:

To a stirred ice-bath cooled solution of acetaldehyde (or other suitable aldehyde, e.g. benzaldehyde) 1.1 mole) in 300 ml. ether (or other suitable solvent, e.g., methyl alcohol or pyridine) is added slowly the appropriate phenylhydrazine (1 mole) and stirring is continued for one hour. The solution is washed with water and the ether layer is separated, dried and evaporated under reduced pressure to give the corresponding acetaldehyde phenylhydrazone which can be purified by standard procedures or used as such in the next step. If pyridine is used as solvent instead of ether, the resulting pyridine solution of the hydrazone is used directly in the next step this quenched in ice-water and the precipitated hydrazone is collected by filtration. If methyl alcohol is used as solvent, the hydrazone generally precipitates and is collected by filtration. To a stirred ice-bath cooled solution of the thus obtained acetaldehyde phenylphydrazone (0.12 mole) in ml. of pyridine is added slowly the appropriate aroyl chloride (slight excess over 0.12 mole) and the resulting mixture is allowed to warm to room temperature and diluted with ice-water. The resulting corresponding acetaldehyde I-aroyl-l-phenylhydrazone, if a solid, is collected by filtration, washed with water and dried; if a gum or oil, the supernatant liquid is decanted, the residue is dissolved in ether and the solution is washed "7 thoroughly'with water, dried and used as suchi'n the next ste'p' Alternatively the acetalde'hyde phenylhydrazone *i's reacted"With a 'slight excess'of' 'sodium hydride in dimethylformamide with- Cooling and'the resulting solution of the'acetaldehyde phenylliydrazone sodiumsaltds-reacted at room temperature with a slight excess of the appropriate aroyl chloride foiseveral hours. The mixture is then treated with a sufficient quantity 'of" glacial acetic acid to neutralize excess base and extracted with ether. The ether'extra'ct iswashed with water, dried, and evaporated to dryness under "reduced pressure. The acetaldehyde 1-'aroyl-l-phenylhydrazone so obtained is purified using standard techniquesor is used as such in the next step. This latter aroylation procedure is preferred when the aroyl chloride and/or the phenylhydrazone bear an ortho-substituent. To a stirred solution orsuspensio'n of the thus obtained corresponding acetaldehyde l-aroyl lphenylhydrazone in ethyl alcohol orin' ether is added a solution of hydrogen chloride (in-excess of one equivalent) in ether or ethyl alcohol respectivelyand stirring then added to aid "the precipitation of the resulting corresponding 1"- aroyl l-phenylhydrazinne hydrochloride which is c'ollected by filtration and washed with ether and generally is used" as such in the next step without -is continued for one hour. If required, additional ether is further purification. The corresponding freehydrazine can be obtained, if desired, by r'eac'tion of the-hydrochloride salt with an equivalent amount of 'ppropriate b'ase, using standard procedures. a

The phenylhydrazines employed in the preparation of the intermediate compounds having Formula VI are known compounds or are readily prepared from the corresponding known anilines, which belong to a well known class of compounds, using standard procedures. For example, a convenient method is the reaction of an appropriately substituted aniline with sodium nitrite in the presence of hydrochloric acid and reduction of-theresulting corresponding phenyldiazonium chloride-awith stannous chloride followed by treatment with sodium'hydroxide to give the corresponding substituted phenylhydrazine.

The aroyl halides employed in the preparation of the intermediate compounds having Formulaare known ,Compounds or are"readily"prepare'd fromthecorresrfibndingknown arylcarboxylicacidsrnsing standard procedures, e.g., by reaction -of an appropriate arylcarboxylic acid with. an appropriate halogenating .agentsuch *as thionyl chloride or oxalylchloride.

The intermediate cyclohexanonel-carboxylic acids having Formula VII (R=H) and certain 'lower-alkyl esters thereof are. known'eompounds. Other lower-alkyl esters theerofw'canbe prepared by standard esterification proceduressuch' as reactiorrof the 'carboxylic acid with and appropriate diazoalkane, for example, diazomethane; by reaction of the carboxylic" acid with an appropriate alcohol (-R'OH,:where*R-is lower-alkyl) inthe'presence of an acid catalyst, for example, sulfuric acid or hydrochloric acid, or in the presence of an equivalent of cyclohexylcarbodiimide; and by -r'eactionof-the :alkali metal salt of the: carboxylic ,acid with thionyl chloride and further reaction of the acid chloride so, formed with an appropriate alcohol,

. The compoundshavingFormula I are prepared" an 8 respectively and further subjectingthe benzyl ester so obtain'ed to hydrogenolysis to give .the corresponding com pound'of Formula Ixwhere R='is hydrogen.

Coin" KB :11 or lower-alkyl) vrn (R=iower-alkyl) perature ranging from about room temperature to about 100 C1 to give the corresponding compound having For- :mulaI (R=lower-alkyl) or corresponding compound havingFormulaIV The hydrogenolysis is carried out by subjecting a solution or suspension of the benzyl ester so obtained, in a suitable solvent, to a hydrogen atmosphere at room or elevated temperatures and a pressure of one or more atmospheres in the presence'of a suitable catalyst until the required amount of hydrogen has reacted. Suitable solvents that can be used areffor example, methyl alcohol, ethyl alcohol, ethyl acetate or acetic acid and the like. Suitable catalysts that .can be used are, for example, nickel, palladium or platinum or such catalysts supported on a suitable medium such as charcoal, e.g. palladium-om charcoal. The aroylation reaction is conveniently carried out by reacting a 9-H--1,2,3,4-tetrahydrocarbazole-3-carboxylic acid lower-alkyl or benzyl ester with an equivalent of sodium hydride in dimethylformamide at about 60 to 100 C. for about fifteen minutes and treating a solution of the sodium salt so obtained with an equivalent of the aroyl halide (IX) and continuing heating at about 60 to 100 C. for about one to two hours, and isolating the resulting corresponding 9-aroyl-1,2,3,4-tetrahydrocarbazole-3-carboxylic acid loWer-alkyl' or benzyl ester by standard procedures. The hydrogenolysis of the benzyl ester so obtained'is conveniently carried out by suspending or dissolving it in ethyl alcohol and subjecting it to a hydrogen atmosphere in the presence of a five to ten percent palladium-on-charcoal, in the amount of-about oneto five percent by weight of benzyl ester, at a temperature rang ing'from room temperature to about C., stopping the reaction when about-the stoichiometric amount of hydrogen has reacted, and-isolating and purifying the correspondingB-carboxylic acid by standard procedures. The compounds having Formula I where R is hydrogen are also prepared by subjecting the corresponding t-butyl ester (I, R=t-butyl) to pyrolytic conditions which selectively remove the t-butyl moiety to give the corresponding free carboxylic acid. The reaction is conveniently carried by heating a mixture of the t-butyl ester with powdered porousplate in a nitrogen atmosphere at about 210 C.

The aroyl-halides (IX) are known compounds or can be readily prepared from the corresponding arylcarbox- 'ylic acids by the known methods described hereinabove.

The intermediate 9-H-1,2,3,4-tetrahydrocarbaz0le-3- carboxylic acids lower-alkyl esters (VIII, R-=lower alkyl) are prepared by the methods more fully described hereinbelow or are prepared by known esteriflcation procedures from the corresponding 9-H-1,2,3,4-tetrahydrocarbazole-3-carboxylic acids (VIII, R=H). For example, an appropriate carboxylic acid can be treated in an alkanol (ROH, where R is lower-alkyl) in the presence of hydrogen chloride to give the corresponding ester; or the cyclohexylcarbodiimide method for preparing esters referred to hereinabove may be employed; or an appropriate carboxylic acid can be converted to the alkali metal salt which is then reacted with a halogenating agent to give the corresponding acid halide. The acid halide so ob.- tained is then reacted with an appropriate alcohol (ROH, where R is lower-alkyl) or its alkali metal salt to give the corresponding ester. A convenient method is reaction of the carboxylic acid with about an equivalent of sodium hydride to give the corresponding sodium salt and further reaction of the salt with thionyl chloride followed by reaction of the carboxylic acid chloride so obtained with the appropriate alcohol or sodium or potassium salt of the alcohol to give the ester (VIII, R=lower-alkyl). The carboxylic esters can also be prepared by the known procedure of reacting the appropriate carboxylic acid with cyclohexylcarbodiimide to give the corresponding symmetrical carboxylic acid anhydride and treating the anhydride so obtained with an appropriate alcohol in the presence of an acid catalyst, for example zinc chloride. The t-butyl esters, intermediates for the pyrolytic' conversion to the compounds of Formula I (R=H)- as described hereinabove, can be conveniently prepared by this latter procedure.

The 9-H-1,2,3,4-tetrahydrocarbazole-3-carboxylic acid benzyl esters (IV, R -=H) can be prepared from the corresponding free carboxylic acids and corresponding known benzyl alcohols using the known esterification procedures described hereinabove. Alternatively, they can be prepared by reacting an alkali metal salt' of an appropriate benzyl bromide or chloride in a suitable solvent. The latter reaction is conveniently carried out byreacting the carboxylic acid with an equivalent of a benzyl chloride and an equivalent of sodium carbonate in'dimeth} ylformamide at about 80-100 C. for about one hour. The benzyl bromides'and chlorides belong to a group of well known compounds and are generally known or can be prepared from the corresponding known toluenes by standard halogenation procedures, e.g. reaction of an appropriate toluene with sulfuryl chloride or N-hromosuccinimide in the presence of a peroxide such as benzoyl peroxide to give the corresponding toluene a chloride or bromide, that is, benzyl chloride or bromide respectively,

The 9-H-1,2,3,4-tetrahydrocarbazole-3-carboxylic acids and their correspondinglower-alkyl esters (VIII) and benzyl esters (IV) can be prepared from the correspond ing phenylhydrazines and cyclohexanone-4-carboxylic acids and its lower-alkyl esters (VII) using thegeneral procedures described hereinabove for the preparationof the tetrahydrocarbazoles having Formula I from the corresponding l-aroyl-l-phenylhydrazines' (VI) and cyclohexanone-4- carboxylic acids (VII). j

It will be understood that in the methods described hereinabove for the preparation of the compounds of the invention having Formula I that, unless otherwise Q, Q1, 1, 'P .g; 'R," 1 2; and Q4: Q5! Q6: Z4 Z5: Z6; m, P gr R1, R and R have the same meaning as defined above for Formulas I and III; and Formula IV, respectively, "except where Q and/or Q represents amino or hydroxy. The compounds of the invention having Formulas I and III where Q and/or Q 'eachincludes one or more hydroxy substituents, and/or Z and/ or Z each includes an amino substituent, are prepared, if desired, from the corre j sponding compounds having Formulas I and" III where Q and/or Q includes one or more benzyloxy sub'stituents, and/or Z and/or Z includes a nitro' substituent, respec tively, by well known catalytic hydrogenation procedures whereby 'said'substituents are converted to hydroxy and/ o'r arn'ino substituents. The hydrogenation is carried out at room temperature in an inert solvent, e.g. ethyl alcohol, under essentially neutral conditions in the presence of a suitable catalyst, e.g. Raney nickel or palladium-on- 5 charcoal, at'about atmospheric pressure and the hydrogenation is stopped after the stoichiometric amount of hydrogen has reacted.

The compounds of the invention having Formula II are prepared, as illustrated in the flow chart below, from the corresponding 9-H-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid lower-alkyl esters (X, R =lower-alkyl) and benzyl esters (V, R =H) using methods similar to those described hereinabove for the preparation of the compounds having Formula I from the 9-H-1,2,3,4-tetrahydrocarbazole-3-carboxylic acid alkyl esters (VIII, R=lower-alkyl) and benzyl esters, (IV, R =H), that is, by aroylation with an appropriate aroyl halide having the Formula XI below, where X is chloride, bromide or fluoride, and, in the case of the benzyl esters so obtained, subsequent hydrogenolysis, or, in the case of the t-butyl ester (II, R =t-butyl), subsequent pyrolysis, to give the corresponding free carboxylic acid (II, R =H) Since hydroxy substituents will also undergo benzoylation during this reaction, compounds of the invention where Q represents hydroxy are prepared from corresponding compounds where Q is benzoyloxy, subsequent to the benzoylation reaction, as more fully disclosed hereinbelow. The aroyl halides (XI) are known compounds or can be'prepared by known methods described hereinbefore for the preparation of the aroyl halides of Formula IX.

The compounds of the invention having Formula II where R3 is loweralkyl, 4-acetamidophenyl, lower-alkanoyloxymethyl, benzoyloxymethyl and benzoyloxymethyl substituted as hereinbefore defined can also be prepared 40 from the free carboxylic acids (II, R =H) by standard esterification procedures as described hereinbefore for the preparation of compounds having Formula I (R/=loweralkyl, 4-acetamidophenyl, lower-alkanoyloxymethyl, benzoyloxymethyl and benzoyloxymethyl substituted as hereinbefore defined) from the corresponding free carboxylic acids (I, R=H).

X(Rz=lower alkyl) The 9-H-1,2,3,4-tetrahydrocarbazole 4 carboxylic acid lower-alkyl esters (X, R =lower-alkyl) and benzyl ,1 esters (V, R =H) used as intermediates in the preparation of the compounds having Formula H are obtained by reacting the corresponding free 4-carboxylic acids (X,

I1 =H) with appropriate known alcohols (R OH, where kg islower-alkyl) or diazoalkanes, and benzyl bromides or chlorides, respectively, usingthe known esterification procedures described hereinabove for the preparation of the 9 H-1,2,3,4-tetrahydrocarbazole 3 carboxylic acid lower-alkylesters (VIII, R=lower-alkyl) and benzyl esters (IV," R I I-) respectively; and in the case where Q, is hydroxy, which substituent is introduced by reductive cleavage of the corresponding compound where Q is a benzyloxy, as described below, such hydroxy substituent is concurrently converted to the corresponding compound where Q; is a benzyloxy substituent, during the preparation of the benzyl ester, or, in the case of the lower-alkyl esters, the hydroxy substituent is converted to a benzyloxy substituent, immediately following the esterification step. The benzyl bromides and chlorides are known compounds or are readily prepared by known halogenating methods from the corresponding toluenes as described hereinabove. The 9-H-1,2,3,4-tetrahydrocarbazole 4 carboxylic acids (X, R =H) used as intermediates in the preparation of the'corresponding lower-alkyl esters (X, R ==loweralkyl) and benzyl esters (V, R =H) are prepared from the corresponding 9-benzyl-1,2,3,4-tetrahydrocarbazole-4- carboxylic acids, having the Formula Xa below, byreductive removal of the benzyl moiety using known hydrogenolysis procedures, that is, alkali metal/ammonia chemical reduction, e.g. sodium in liquid ammonia; and in the case where Q; is a benzyloxy substituent, the benzylmoiety will concurrently undergo reductive removal to give the corresponding compound where Q, is hydroxy. The 9- benzyl group can be unsubstituted on phenyl or substituted on phenyl, for example, by halo, alkyl, or alkoxy substituents so long as such substitution does not prevent or interfere with the subsequent reductive removal of the 9-benzyl group. I

The intermediate 9-benzyl compounds having Formula Xa are prepared, as illustrated below, by reaction of at last two equivalents of an appropriate phenylbenzylamine (XII) with one equivalent of an appropriate -bromocyclohexanone-Z-carboxylic acid methyl or ethyl ester (XIII), in a suitable solvent if desired, to give the corresponding intermediate 6 anilino-cyclohexanone-2-carboxylic acid ester (XIV) which is then heated with a suitable acid catalyst, e.g. zinc chloride, to effect cyclization to the corresponding 9-benzyl-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid ester. The ester so obtained is then hydrolyzed, using standard procedures, to the corresponding free' 4- carboxylic acid (Xa).

COzMG (or Et) The reaction is convenientlycarried out by mixing together a bromocyclohexanonecarboxylic acid ester (XIII) and two to two and one-half equivalents of a phenylbenzylamine (XII) and allowing themixture tofstand at;from about 20 C. to 100 C. for from one-half,to twenty-four hours, depending on the reaction temperature'femployed,

to give the intermediate anilinocyclohexa ridne (XIV). Depending on the nature of the reactants, the' reaction can be performed in the absence of solvent or a suitable solvent such as benzene may be desirable. The intermediate anilinocyclohexanone (XIV) is then heated with zinc chlorideat about to 200 C. for about one-half to two hours and the corresponding 9-benzyl-l,2,3,4-tetrahydrocarbazole-4-carboxylic acid ester so obtained is treated with potassium hydroxide in aqueous ethyl or methyl alcohol to give the free carboxylic acid (Xa).

The 6 bromocyclohexanone-Z-carboxylic acid esters (XIII) used as intermediates in the above described procedure are known compounds or can be readily prepared by reacting the corresponding known cyclohexanone-Z- carboxylic acid esters with bromine in a suitable solvent. The reaction is conveniently carried out by treating a cooled solution of the appropriate cyclohexanone-Z-carboxylic acid ester in ether or carbon tetrachloride with an equivalent or slight excess of bromine, allowing the solution to stand at room temperature for about one hour, and isolating the resulting 6-bromocyclohexanone-2-carboxylic acid ester by standard techniques.

The intermediate phenylbenzylamines (XII) are known compounds or are readily prepared by standard procedures from the corresponding known anilines and corresponding known benzaldehydes as follows:

To a stirred warm solution of an appropriate aniline (1.0 mole) in 400 ml. dry methyl alcohol is added dropwise an appropriate benzaldehyde and the solution is heated at reflux for thirty minutes and then cooled on ice. The resulting Schitf base is collected by filtration and Washed with methyl alcohol. To a suspension of the latter in methyl alcohol is added portionwise, sodium borohydride 1.0 mole) and the mixture is refluxed about fifteen to thirty minutes after completion of the addition. Water (200 ml.) is added and the mixture is extracted with ether and the ether extract is dried and evaporated to dryness to give the corresponding phenylbenzylamine which is used as such in the next' step, or, if desired, is purified by standard procedures before use. d

. It will be understood that in the methods described hereinabove for the preparationof the compounds of the invention having Formula II that, unless otherwise in; d Q7: Q8! Q9! Z7: Z8: Z9; PM? R5, R and R have thesa-me meaning as defined above for'Formulas 'II}and V respectively. The compounds of the invention having Formula II where Q, and/or Q each includes oneor more hydroxy substituents are prepared, if desired, from the corresponding compounds having Formula V where Q) and/or Q respectively, includes'one ,or more benzyloxy substituents, by known catalytic hydrogeriation procedures as described hereinabove for the preparationof compounds of Formula I where Q and/or Q includes one or more hydroxy substituents.

The compounds of the invention having Formulas I and II were found to have antiinflammatory activity as determined by their'ability to inhibit asbestos pellet induced grarruloma weight increase, carrageenin-induced foot edema' and, adjuvant-induced arthritis in rats and are useful as antiiriflammatory agents. v i

The following arebrief descriptionsof the pharmacological testprocedures used to determine the above disclosed antiinfiammatory activity of the compounds of this invention:

ASBESTOS PELLET GRANULOMA TEST IN RATS M Young male. rats"weighing100120 g. are used. Under lightether anesthesia, a single sterilized asbestos pellet weighingapproximately 30 mg. is implanted subcutaneously inthe interscapulartareavia a small skin incision and closed with a wound clip. In any one assay, the pellet weights are withina 2 mg. rangeJBeginningon the day of pelletimplantation, the animals receive 7 daily medications of test compound'suspended by triturating in 1% gum tr'agacanthjusing a ground glass homogenizer and administered by gavage in a volume of 1 ml./ 100 g. body weight, Control animals receive the vehicle only. Food INHIBITION OF CARRAGEEIN-INDUCED FOOT EDEMA IN RATS Young male rats weighing 100-110 g. are used. Food is withdrawn approximately 18 hours prior to medication but the animals are permitted free access to drinking water up to the time of medication. Drugs to be tested are suspended by triturating in 1% .gum tragacanth using ground glass homogenizers and administered by gavage in a volume of 1 ml./ 100 g. body weight. Control animals receive the gum tragacanth only. One hour after medication, 0.05 ml. of 1% suspension of carrageenin in 0.9% saline is injected into the plantar tissue of the left hind paw. Three hours after injection of the carrageenin, edema formation, i.e., increase in foot volume (difference between left hind paw and the uninjected right hind paw) is measured plethysmorpraphically in the unanesthetized rat.

INHIBITION ADI UVANT-INDUCED ARTHRITIS IN RATS Adult male rats weighing 200-230 grams are used. Adjuvant (M. butyricum'), 0.1 ml. of a 0.6% suspension in heavy mineral oil, is injected into the plantar tissue of the left hind paw. A negative control group is injected with mineral oil only. Beginning on the ninth day after adjuvant injection (polyarthritis does not appear until approximately the tenth day after adjuvant administration), the animals receive 6 daily medications of test compound suspended by triturating in 1% gum tragacanth using a ground glass homogenizer and administered by gavage in a volume of 1 ml./100 g. body weight. Both the negative control and adjuvant injected control animals receive the vehicle only. Food and Water are permitted ad libitum. Twenty-four hours after the last medication,- the animals are weighed, the degree of arthritic involvement, i.e., increase in foot volume and plasma inflammation units are determined. Foot volume is measured plethysmographically in the unanesthetized art.

The compounds of the invention having Formulas I and II' were found to be effective as antiinflammatory agents when administered to rats, as disclosed hereinabove, in the amounts of 40 to 160 mg. per kilogram of body weight per dosage unit depending upon the compound used and the condition to be treated. The actual determination of the numeral biological date definitive for a particular compound is readily determined by standard test procedures by technicians having ordinary skill in pharmacological test procedures, without the'need for any extensive experimentation. I

The compounds having Formulas I and II an'dtheir pharmaceutically acceptable salts can be prepared for use by conventional pharmaceutical procedures; that is, they can be incorporated in unit dosage form in tablets or capsules for oral administration either alone or in combination with suitable adjuvants such as calcium carbonate, starch, lactose, talc, magnesium stearate, gum acacia, and

the like; or as aqueous or oil suspensions or solutions in a pharmaceutically acceptable vehicle such as aqueousalcohol, glycol, oil solutions or oil water emulsions for oral or parenteral administration.

The molecular structures of the compounds of this invention were assigned on the basis of the method of their 14 Example 1 (A) 9-benzoyl-1,2,3,4-tetrahydrocarbazo1e-3-carboxylic acid.9 benzoyl-l,2,3,4-tetrahydrocarbazole 3,3 dicarboxylic acid (3.7 g.) was heated at 170200 C., till carbon dioxide evolution ceased, to give 2.5 g. of the title compound; M.P. 188-190 C. (benzene).

(A1 9-benzoy1-1,2,3,4-tetrahydrocarbazole-3-carboxylic acid (alternative preparati0n).-A suspension of 30 g. of benzaldehyde l-benzoyl-l-phenylhydrazone (M.P. 112114 C.) and 14.2 g. of cyclohexanone-4-carboxylic acid in ml. glacial acetic acid containing 5 g. of concentrated sulfuric acid was heated on a steambath at about 95 C. for three and one-half hours. The mixture was poured into one liter of ice-cold water with stirring. The water was decanted from the resulting gummy residue which was then crystallized from ethyl acetate and recrystallized from ethyl alcohol to give 17 g. of the titled compound; M. P. 188-192 C.

(B) 9-benzoyl-1,2,3,4-tetrahydrocarbazole 3,3 dicarboxylic acid.1-benzoyl-l-phenylhydrazine hydrochloride (5 g.) and 4 g. of cyclohexanone-4,4-dicarboxylic acid in 10 ml. of glacial acetic acid were heated at 60- 70 C. for thirty minutes. The mixture was diluted with water and the resulting solid was collected by filtration and washed with water to give 7.1 g. of the title compound; M.P. C. (acetone and hexane).

Example 2 (A) 9-( 4-chlorobenzoyl)-1,2,3 ,4 tetrahydrocarbazole- 3-carboxylic acid.Following a procedure similar to that of Example 1(A) but using 3.7 g. of 9(4-chlorobenzoyl)- 1,2,3,4 tetrahydrocarbazole-3,3-dicarboxylic acid there was obtained 2.5 g. of the title compound; M.P. 210211 C. (benzene-hexane).

(B) 9-(4-chlorobenzoyl)-1,2,3,4 tetrahydrocarbazole- 3,3-dicarboxylic acid.Following a procedure similar to that of Example 1(B) but using 10.7 g. of 1-(4-chlorobenzoyl)-l-phenylhydrazine hydrochloride and 13 g. of cyclohexanone-4,4-dicarboxylic acid there was obtained crude product, a solution of which in ether was extracted with potassium bicarbonate solution. Acidification of the bicarbonate extract with 10% hydrochloric acid and collection of the resulting solid by filtration yielded 2.7 g. of the title compound; M.P. 210-2l2 C. (ethyl acetatebenzene).

Example 3 (A) 9-benzoyl-6,7-dimethoxy-1,2,3,4 tetrahydrocarbazole-3-carboxylic acid.Following a procedure similar to that of Example 1(A) but using 5 g. of 9-benzoyl-6,7-dimethoxy l,2,3,4 tetrahydrocarbazole-3,3-dicarboxylic acid there was obtained 2.5 g. of the title compound; M.P. 191194 C. (benzene-hexane).

(B) 9-benzoyl-6,7-dimethoxy-1,2,3,4 tetrahydrocarbazole-3,3-dicarboxylic acid.Following a procedure similar to that of Example 1(B) but using 9.3 g. of 1-benzoyl- 1-(3,4-dimethoxyphenyl) hydrazine hydrochloride (M.P. ISO-156 C.) and 6 g. of cyclohexanone-4,4-dicarboxylic acid there was obtained 8 g. crude title compound used directly in the next step; M.P. of purified title compound, 222 C. dec. (benzene).

Example 4 boxylic acid.Following a procedure similar to that of Example 1(B) but using 5.4 g. of 1-(4-toluoyl)-1-phenylhydrazine hydrochloride (M.P. 176 C.) and 4.5 g. of cyclohexanone-4,4-dicarboxylic acid there was obtained 7.2 g. of the title compound; M.P. -195 C.

Example 5 (A) 9-(4-fluorobenzoyl)-1,2,3,4-tetrahydrocarbazole-3- carboxylic acid.'Following a procedure similar to that of Example 1(A) but using 4.3 g. of 9-(4fluorobenzoyl)- 1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid there was obtained 3.2 g. of the title compound; M.P. 180- 182 C. (acetone-hexane).

(B) 9-(4-fluorobenzoyl) 1,2,3 ,4-tetrahydrocarbazole-3 3-dicarboxylic acid.Following a procedure similar to that of Example 1(B) but using 5.8 g. of 1-(4-fiuorobenzoyl)-lphenylhydrazine hydrochloride (M.P. 173-177 C.) and 4.5 g. cyclohexanone-4,4-dicarboxylic acid there was obtained 7 g. of the title compound; M.P. 190-195 C.

Example 6 (A) 9-(4-anisoyl)-1,2,3,4-tetrahydrocarbazole 3 carboxylic acid.Following a procedure similar to that of Example 1(A) but using 5.6 g. of 9-(4-anisoyl)-l,2,3,4- tetrahydrocarbazole-3,3-dicarboxylic acid there was obtained 3.3 g. of the title compound; M.P. 195 C.

(B) 9-(4-anisoyl)-1,2,3,4-tetrahydrocarbazole 3,3 dicarboxylic acid.Following a procedure similar to that of Example 1(B) but using 4.6 g. of 1-(4-anisoyl)-lphenylhydrazine hydrochloride (M.P. 168170 C.) and 3.6 g. of cyclohexanone-4,4-dicarboxylic acid there was obtained 3.3 g. of the title compound; M.P. 205-207 C. (benzene-hexane) Example 7 (A) 9(3,4,5 trimethoxybenzoyl) 1,2,3,4 tetrahydrocarbazole-3-carboxylic acid.Following a procedure similar to that of Example 1(A) but using the 9-(3,4,5- trimethoxybenzoyl) 1,2,3,4 tetrahydrocarbazole-3,3- dicarboxylic acid obtained in 7(B) below there was obtained 5 g. of the title compound; M.P. 234-236 C.

(B) 9-(3,4,5 trimethoxybenzoyl) 1,2,3,4 tetrahydrocarbazole 3,3 dicarboxylic acid.-Fllowing a procedure similar to that of Example 1(B) but using 5.4 g. of 1-(3,4,5 trimethoxybenzoyl) 1 phenylhydrazine hydrochloride and 3.6 g. of cyclohexanone 4,4- dicarboxylic acid there was obtained the title compound; M.P. 208 C.

Example 8 (A) 9-(3-toluoyl) 1,2,3,4 tetrahydrocarbazole 3- carboxylic acid-Following a procedure similar to that of Example 1(A) but using 4.3 g. of 9-(3-toluoyl)-l,2,3, 4 tetrahydrocarbazole 3,3 dicarboxylic acid there was obtained 3.2 g. of the title compound; M.P. ISO-182C.

(B) 9-(3-toluoyl) 1,2,3,4 tetrahydrocarbazole 3, 3 dicarboxylic acid.--Following a procedure similar to that of Example 1(B) but using 5 .6 g. of 1-(3-toluoyl)-1- phenylhydrazine hydrochloride (M.P. 170-172 C.) and 4.5 g. of cyclohexanone 4,4 dicarboxylic acid there was obtained 6.6 g. of the title compound; M.P. 195- 200 C. 7

Example 9 9-benzoyl 6 methyl 1,2,3,4 tetrahydrocarbozole- 3 carboxylic acid.Following a procedure similar to that of Example 1(B) but using 10.6 g. of l-benzoyl-l- (4-tolyl) hydrazine hydrochloride (M.P. 155 C. dec.) and 6.5 g. of cyclohexanone 4 carboxylic acid there was obtained 9.6 g. of the title compound; M.P. 200-202 C. (acetone-water).

Example 10 9-(4 fluorobenzoyl) 6 methyl 1,2,3',4 tetrahydrocarbazole 3 carboxylic acid-Following a procedure similar to that of Example 1(B) but using 15.6 g. of 1-(4 fluorobenzoyl) 1 (4-tolyl) hydrazine hydrochloride (M.P. 155 C. dec.) and 8.4 g. of cyclohexanone- 4-carboxylic acid there was obtained 12.7 g. of the title compound; M.P. 230-233 C. (acetone-water).

water).

1 6 Example 1 1 9-[3-(trifluoromethyl)benzoyl] 1,2,3,4 tetrahydrocarbazole 3 carboxylic acid.-Following a procedure similar to that of Example 1(B) but using 10 g. of 1-[3- (trifiuoromethyl)benzoyl] l phenylhydrazine hydrochloride and 5.73 g. of cyclohexanone 4 carboxylic acid there was obtained 8.8 g. of the title compound; M.P. 173-175" C. (ether-hexane).

Example 12 9-(4-t-butylbenzoyl) 1,2,3,4 tetrahydrocarbazole-3- carboxylic acid.-Following a procedure similar to. that of Example 1(B) but using 19 g. of 1-(4-t-butylbenzoyl)- 1 phenylhydrazine hydrochloride and 10.7 g. of cyclohexanone 4 carboxylic acid there was obtained 13.7 g. of the title compound; M.P. 174-175 C. (acetonewater).

Example 13 9 (3 bromobenzoyl) 1,2,3,4 tetrahydrocarbazole- 3-carboxylic acid.-Following a procedure similar to that of Example 1(B) but using 10.7 g. of 1-(3-bromobenzoyl)- l-phenylhydrazine hydrochloride and 5.35 g. of cyclohexanone 4 carboxylic acid there was obtained 10.2 g. of the title compound; M.P. 186 C. (acetonewater).

Example 14 9-(4-toluoyl)-6-methyl 1,2,3,4 tetrahydrocarbazole- 3 carboxylic acid.-Following a procedure similar to that of Example 1(B) but using 3.8 g. of 1-(4-toluoyl)- 1 (4 tolyl) hydrazine hydrochloride (M.P. 273-275 C.) and 2.22 g. of cyclohexanone 4 carboxylic acid there was obtained 3 g. of the title compound; M.P. 200- 203 C. (isopropyl alcohol).

' I 9 Example 16 9-(4 t0luoyl) 6-fluoro 1,2,3,4 tetrahydrocarbazole- 3 carboxylic acid.Following a procedure similar to that .of Example 1 (B) but using 10 g. of 1-(4-toluoyl) 1- (4 fluorophenyl) hydrazine hydrochloride and 5.23 of cyclohexanone 4 carboxylic acid therewas obtained 9.7 g. of the title compound; M.P. 229-231 C. (acetone- Example 17 f i 9(4-fluorobenzoyl) 6 fluoro 1,2,3;4 tetrahydrocarbazole 3 carboxylic acid-Following aprocedure similar to that of Example 1(B) but using 12.2 g. fof 1- 4-fluorobenzoyl) 1 (4 fiuorophenyl) hydrazine hydrochloride (M.P. 175,C. dec.) and 6.5 g. of cyclohexanone 4 carboxylic acid there was obtained 12.2

g. of the title compound; M.P. -l96 C. (acetonewater).

Example 18 9 (4 anisoyl) 6 methyl 1,2,3,4 tetrahydrocarbazole 3 carboxylic acid-Following a procedure similar to that of Example 1(B) but using 3.3 g. of 1-(4-anisoyl) 1 (4-tolyl) hydrazine hydrochloride (M.P. 149-153 C.) and 1.91 g. of cyclohexanone-4- carboxylic acid there was obtained 5.1 g. of the title compound; M.P. 172-173" C. (isopropyl alcohol).

Example 19 9-(4-anisoyl)6-fluoro 1,2,3,4 tet rahydrocarhazole- 3-carboxylic acid.Following a procedure similar to'that of Example 1(B) but using 14 g. of 1-(4 -anisoyl)-1 -(4- 17 fluorophenyl) hydrazine hydrochloride and 7.03 g. of cyclohexanone-4-carboxylic acid there was obtained 13.5 g. of the title compound; M.P. 197198 C. (acetonewater).

Example 20 9-(4-chlorobenzoyl)-6-methoxy 1,2,3,4 tetrahydrocarbazole-3-carboxylic acid.--Following a procedure similar to that of Example 1(B) but using 11 g. of 1-(4-chlorobenzoyl) 1 (4-methoxyphenyl) hydrazine hydrochloride and 6.2 g. of cyclohexanone-4-carboxylic acid there was obtained 3.2 g. of the title compound; M.P. 269-273 C. (tetrahydrofuran-ether) Example 21 9-benzoyl-6-methoxy 1,2,3,4 tetrahydrocarbazole-3- carboxylic acid-Following a procedure similar to that of Example 1(B) but using 8.9 g. of 1-benzoyl-1-(4-methoxyphenyl) hydrazine hydrochloride and 4.97 g. of cyclohexanone-4-carboxylic acid there was obtained 8.9 g. of the title compound; M.P. 216-219 C. (acetonewater).

9-benzoyl-6-methoxy 1,2,3,4 tetrahydrocarbazole-3- carboxylic acid (alternative preparation).-A solution of 75 g. of benzaldehyde l-benzoyl-l-(4-methoxyphenyl)- hydrazone and 42.6 g. of cyclohexanone-4-carboxylic acid in one liter of acetic acid saturated with hydrogen chloride was heated under reflux for three hours during which time hydrogen chloride was continually passed through the solution. The solution was poured into four liters of icewater and the resulting solid was collected by filtration to give 47.4 g. of the title compound; M.P. 218220 C. (methyl alcohol).

The benzaldehyde l-benzoyl 1 (4-methoxyphenyl) hydrazone was prepared as follows: To a solution of 69 g. of 4-methoxyphenylhydrazine in one liter of methyl alcohol was added 53 g. of benzaldehyde and the mixture was heated under reflux for one-half hour. The mixture was cooled to C., filtered, and the benzaldehyde 4- methoxyphenylhydrazone (M.P. 126-129 C.) was dissolved in 450 ml. pyridine and 63 g. of benzoyl chloride was then added during five minutes with stirring and water bath cooling. After one-half hour the reaction mixture was poured into two liters of ice-water and the solids were collected by filtration to give 119 g. of benzaldehyde l-benzoyl 1 (4-methoxyphenyl)hydrazone; M.P. 151- 153 C. (isopropyl alcohol).

Example 22 9-(4-chlorobenzoyl)-6-methyl 1,2,3,4 tetrahydrocarbazole-3-carboxylic acid.Following a procedure similar to that of Example 1(B) but using 16.5 g. of 1-(4-chlorobenzoyl)-1-(4-tolyl) hydrazine hydrochloride and 9.93 g. of cyclohexanone-4-carboxylic acid there was obtained 8.9 g. of the title compound; M.P. 211-214 C. (isopropyl alcohol).

Example 23 9 (4-fluorobenzoyl)-6-methoxy-1,2,3,4-tetrahydrocarbazole-3-carboxylic acid.Following a procedure similar to that of Example 1(B) but using 6.3 g. 1-(4-fluorobenzoyl)-1-(4-methoxyphenyl) hydrazine hydrochloride and 2.98 g. of cyclohexanone-4-carboxylic acid there was obtained 3.7 g. of the title compound; M.P. 258260 C. acetone-water) Example 24 9-(4-toluoyl)-6-methoxy 1,2,3,4 tetrahydrocarbazole- 3-carboxylic acid.Following a procedure similar to that of Example 1(B) but using 5.6 g. of 1-(4-toluoyl)-1-(4- methoxyphenyl) hydrazine hydrochloride and 3.7 g. of cyclohexanone-4-carboxylic acid there was obtained 7 g. of the title compound; M.P. 257258 C.

Example 25 9 (3-anisoyl)-l,2,3,4-tetrahydrocarbazole-3-carboxylic acid.Following a procedure similar to that of Example 18 1(B) but using 11 g. of 1-(3-anisoyl)-1-phenylhydrazine hydrochloride and 6.1 g. of cyclohexanone-4-carboxylic acid there was obtained 11.2 g. of the title compound; M.P. 197-200 C. (acetone-water).

Example 26 9-(4-ethoxybenzoyl) 1,2,3,4 tetrahydrocarbazole-3- carboxylic acid.-Following a procedure similar to that of Example 1(B) but using 9 g. of 1-(4-ethoxybenzoy1)- l-phenylhydrazine hydrochloride and 5 g. of cyclohexanone-4-carboxylic acid there was obtained 5.2 g. of the title compound; M.P. 179-182 C. (acetone-water).

Example 27 9-(3,4-methylenedioxybenzoyl) 1,2,3,4 tetrahydrocarbazole-3-carboxylic acid.--Following a procedure similar to that of Example 1(B) but using 13.6 g. of 1-(3,4- methylenedioxyhenzoyl) 1 phenylhydrazine hydrochloride (M.P. -185 C.) and 6.64 g. of cyclohexanone- 4-carboxylic acid there was obtained 13.4 g. of the title compound; M.P. l98200 C. (acetone-water).

Example 28 9-(3-chlorobenzoyl) 1,2,3,4 tetrahydrocarbazole-3- carboxylic acid.-Following a procedure similar to that of Example 1('B) but using 11.2 g. of 1-(3-chlorobenzoyl)-1- phenylhydrazine hydrochloride and 6.12 g. of cyclohexanone-4-carboxylic acid there was obtained 11.5 g. of the title compound: M.P. l79l8l C. (ether-hexane).

Example 29 9-(3-iodobenzoyl)-l,2,3,4-tetrahydrocarbazole 3 carboxylic acid.-Following a procedure similar to that of Example 1(B) but using 21.7 g. of 1-(3-iodobenzoyl)-lphenylhydrazine hydrochloride and 0.5 g. of cyclohexanone-4-carboxylic acid there was obtained 11.5 g. of the title compound; M.P. 210212 C. (acetone-water).

Example 30 9-benzoyl-6-benzyloxy 1,2,3,4 tetrahydrocarbazole-3- carboxylic acid.--Following a procedure similar to that of Example 1('B) but using 15.5 g. of 1-benzoyl-1-(4- benzyloxyphenyl)hydrazine hydrochloride and 6.4 g. cyclohexanone-4-carboxylic acid there was obtained 16.3 g. of the title compound; M.P. 193194 C. (acetone-water).

Alternatively the 9 -benzoyl 1,2,3,4 tetrahydrocarbazole-3-carboxylic acids above (Examples 9 to 30 inclusive) can be prepared following a procedure similar to that of Example 1(A) but substituting for 9-benzoyl-1,2, 3,4tetrahydrocarbazole-3,3-dicarboxylic acid an equivalent amount of the following:

(21-13) 9-benzoyl-6-methoxy-1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(a-14) 9-(4-chlorobenzoyl)-6-methyl-1,2,3,4,-tetrahydrocarbazole-3,3-dicarboxylic acid;

(a-15) 9-(4-fluorobenzoyl)-6-methoxy-1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(a-16 9- (4-toluoyl) -6-methoxy-l,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(a-l7) 9-(3-anisoyl)-l,2,3,4-tetrahydrocarbazole-3,3-

dicarboxylic acid;

(a-18) 9- (4-ethoxybenzoyl -1,2,3,4-tetrahydrocarbazole 3,3-dicarboxylic acid;

(a-19) 9-(3,4-methylenedi0xybenzoyl)-1,2,3,4-tetrahydrocarbazole-El,3-dicarboxylic acid;

(a-20) 9- 3-chlorobenzoyl -1,2,3 ,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(a-21) 9-(3-iodobenzoyl)-1,2,3,4-tetrahydrocarbazole- 3,3-dicarboxylic acid; and

(a-22) 9-benzoyl-6-benzyloxy-1,2,3,4,-tetrahydrocarbazole-3,3-dicarboxylic acid.

The intermediate 9-benzoyl-1,2,3,4-tetrahydrocarbazole- 3,3-dicarboxylic acids above (a1 to a-22) can be obtained by substituting for cycloheXanone-4-carboxylic acid in Examples 9 to 30 inclusive, equivalent amounts of cyclohexanone-4,4-dicarboxylic acid.

Example 31 Ethyl 9-(4-toluoyl)-1,2,3,4-tetrahydrocarbazole-3-carbxylate.1-(4-toluoyl)-1 phenylhydrazine hydrochloride (13 g.) and 8.7 g. of ethyl cyclohexanone-4-carboxylate (perpared in situ from the corresponding ethylene ketal) in 40 ml. glacial acetic acid, and ml. glacial acetic acid saturated with hydrogen chloride was warmed on a steam bath for thirty minutes, diluted with water and extracted with ether. The ether extracts were washed with potassium bicarbonate solution and water, dried, and evaporated to dryness. The residue was chromatographed on silica gel using ether-pentane as eluant to give 12.7 g. of the title compound; M.P. 7072 C. (hexane-ether) Example 32 Ethyl 9-benzoyl-1,2,3,4 tetrahydrocarbazole-3-carboxylate.Following a procedure similar to that of Example 31 and using 11 g. of l-benzoyl-l-phenylhydrazine hydrochloride and 7.62 g. of ethyl cyclohexanone- 4-carboxylate (prepared in situ from the corresponding ethylene ketal) there was obtained 6.2 g. of the title compound; M.P. 6769 C. (ether-pentane).

Example 33 9-benzoyl-2,4-dimethyl-1,2,3,4 tetrahydrocarbazole-3- carboxylic acid.Following a procedure similar to that of Example 1(B) but using 6.5 g. of l-benzoyl-l-phenylhydrazine hydrochloride and 4.6 g. 3,5-dimethylcyclohexanone-4-carboxylic acid and dissolving the resulting solid so obtained in five percent potassium bicarbonate solution followed by reprecipitation with dilute hydrochloric acid there was obtained 4.2 g. of the title compound; M.P. 142-145 C. (ether-hexane).

'Example 34 (A) 9-benzoyl-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid.A solution of 5.6 g. benzoyl-1,2,3,4-tetrahydrocarbazole-4-carboxylate in 250 ml. ethyl alcohol containing 0.5 g. 10% palladium-on-charcoal was subjected to a hydrogen atmosphere at 40 p.s.i., while being heated with an infrared lamp and agitated, until uptake of hydrogen ceased. The mixture was filtered, the filtrate was evaporated to dryness under reduced pressure, the resulting residue was dissolved in ether, the ether solution was extracted with dilute potassium bicarbonate, the bicarbonate extract was acidified with 3 N-hydrochloric acid andextracted with ether and the ether extract was dried and evaporated to dryness. The resulting residue. was crystallized from ether-pentane and a solution of the resulting crystals in 5% potassium bicarbonate soluiton was acidified with 3 N-hydrochloric acid and the resulting solid was filtered and washed with water to give 1.3 g. of the title compound; M.P. 7080 C.

To an ice cold solution of 28 g. of 9-benzoyl-1,2,3,4- tetrahydrocarbazole-4-carboxylic acid in ml. dry methyl alcohol was added slowly a solution of 4.55 g. of 87% potassium hydroxide in the minimum required amount of dry methyl alcohol. The solution was diluted to one liter with anhydrous ether and the solid which formed on scratching the side of the reaction flask was collected by filtration. A second crop was obtained on further dilution. There was obtained 22 g. of potassium 9-benzoyl-1,2,3,4tetrahydrocarbazole-4- carboxylate; M.P. 254-256 C. (dec.).

(B) Benzyl 9-benzoyl-1,2,3,4-tetrahydrocarbazole-4- carboxylate.To 0.85 g. sodium hydride in 150 ml. of dry dimethylformamide was added, portionwise, 9 g. of benzyl 1,2,3,4-tetrahydrocarbazole-4-carboxylate. The mixture was heated on a steam bath for fifteen minutes, the heat was removed, 4 ml. benzoyl chloride was added dropwise to the still hot mixture and heating was resumed for two hours. The mixture, after standing overnight at room temperature, was poured into water containing 4 ml. glacial acetic acid and the resulting mixture was extracted with ether. The ether extract was washed with sodium bicarbonate solution and water, dried, and evaporated to dryness. The resulting residue in 50 ml. dimethylformamide was again treated with 0.42 g. sodium hydride and 2 ml. benzoyl chloride was chromatographed on a 45 mm. by 620 mm. silica gel column using as eluant hexane and hexane containing. increasing amounts of ether. There was thus obtained with 7.5% ether in hexane, after evaporation to dryness and recrystallization, 4.6 g. of the title compound; M.P. 107-109 C. (methyl alcohol).

(C) Benzyl 1,2,3,4 tetrahydrocarbazole-4-carboxylate.-- A stirred mixture of 13 g. l,2,3,4-tetrahydrocarbazole-4-carboxylic acid, 7.8 g. benzyl chloride and 6.5 g. sodium carbonate in dry dimethylformamide was heated on a steam bath for one hour and filtered. The dimethylformamide was evaporated under reduced pressure and the resulting oil was taken up in ether. The ether solution was washed with water, dried and evaporated to give, after recrystallization, 15.5 g. of the title compound, M.P. 108- 112 C. (heptane).

(D) 1,2,3,4 tetrahydrocarbazole-4-carboxylic acid.- To 40 g. 9-benzyl-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid in one liter of liquid ammonia was added, with stirring and portionwise, 8.6 g. of sodium. Ammonium chloride was added portionwise until the blue color of the mixture was dissipated. The ammonia was evaporated, water was added and the mixture was extracted with ether. The aqueous solution was chilled and acidified with dilute hydrochloric acid and the resulting solid was collected by filtration and washed with water to give 23 g. of the title compound; M.P. 163-165 C. (benzenemethyl alcohol).

(E) 9 benzyl-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid.A mixture of 53 g. of phenylbenzylamine and 30 g. of ethyl 6-bromocyclohexanone-2-carboxylaet was maintained in a nitrogen atmosphere at 35 C. for several days. Fused powdered zinc chloride (48 g.) was added and the mixture was heated at -130 C. for one and one-half hours. The cooled mixture was slurried in water and extracted with ether. The ether extract was washed with 5% hydrochloric acid and water, dried, and evaporated to dryness to give 38.5 g. crude ethyl ester of the title compound which was treated with a solution of 48 g. potassium hydroxide in 200 ml. water and 200 m1. ethyl alcohol at reflux temperature for three hours. The solution was evaporated to dryness under reduced pressure, the resulting residue was dissolved in water and the aqueous solution was extracted with ether and acidified with 10% hydrochloric acid. The resulting solids were collected and 21 dried to give 27.4 g. of the title compound; M.P. 212- 215 C. (tetrahydrofuran-pentane).

(F) Preparation of ethyl 6-bromocyclohexanone-2-carboxylate-To a stirred solution of 31 g. of ethyl cyclohexanone-2-carboxylate in 25 ml. of ether, cooled to 10 C., was added dropwise 35 g. of bromine. Stirring was continued one hour while the solution was allowed to come to room temperature. The solution was poured into ice water containing 20 g. sodium carbonate and was extracted with ether. The ether extract was washed with water, dried and evaporated to dryness to give 23 g. of the title compound; B.P. 88-91" C. (0.2 mm.).

EXAMPLE 35 (A) 9 (4-toluoyl)-l,2,3,4-tetrahydrocarbazole-4-carboxlic acid-Following a procedure similar to that of Example 34(A) but using the crude benzyl 9-(4-toluoyl)- 1,2,3,4-tetrahydrocarbazole-4-carboxylate, from Example 35 (B) below, in 250 ml. ethyl acetate and 0.5 g. of 10% palladium-on-charcoal there was obtained 2.6 g. of the title compound; M.P. 181183 C. (ether-hexane) (B) Benzy 9-(4-toluoyl)-1,2,3,4-tetrahyrocarbazole-4- carboxylate.To a steam bath warmed mixture of 1.5 g. sodium hydride in 25 ml. of dry dimethylformamide was added, dropwise and with stirring, 9.15 g. of benzyl 1,2,3,4- tetrahydrocarbazole-4-carboxylate in 25 ml. dry dimethylformamide followed by 5.4 g. of 4-toluoyl chloride in 15 ml. dry dimethylformamide, and heating was continued for two hours. The mixture was cooled and diluted with ether and 1.5 m1. glacial acetic acid. Water was added, the layers were separated and the ether extract was washed with water, 5% potassium bicarbonate solution, 1% aqueous hydrochloric acid and water, and dried over magnesium sulfate. The ether was evaporated to give the title compound which was used without purification in the next step.

EXAMPLE 36 (A) 9 benzoyl-6-methoxy-l,2,3,4-tetrahydrocarbazole- 4-carboxylic acid.A solution of 6.7 g. of benzyl 9- benzoyl 6 methoxy-1,2,3,4-tetrahydrocarbazole-4-carboxylate in 250 ml. of ethyl acetate was hydrogenated over 1 g. palladium-on-charcoal until the required amount of hydrogen had reacted. The mixture was filtered and the filtrate was evaporated to dryness under reduced pressure. The residue was slurried in ether and the resulting solid was collected by filtration to give 1.8 g. of the title compound; M.P. 157-159 C.

(B) Benzyl 9-benzoyl-6-methoxy-1,2,3,4-tetrahydrocarbazole-4-carboxylate.-Following a procedure similar to that of Example 35(B) but using 0.67 g. sodium hydride, 37 ml. of dry dimethylformamide, 7.5 g. of benzyl 6- methoxy 1,2,3,4-tetrahydrocarbazole-4-carboxylate, and 2.9 ml. benzoyl chloride there was obtained 10.6 g. of residue which was triturated in hot hexane to give 6.7 g. of the title compound which was used without further purification in the next step.

(C) Benzyl 6 methoxy-1,2,3,4-tetrahydrocarbazole-4- carboxylate.Following a procedure similar to that of Example 34(C) but using 37.2 g. of 6-methoxy-1,2,3,4- tetrahydrocarbazole-4-carboxylic acid, 19.5 g. of benzyl chloride and 16.8 g. of sodium carbonate in 300 ml. of dry dimethylformarnide there was obtained 40.3 g. of the title compound; M.P. 81-83 C. (ethyl alcohol-pentane).

(D) 6-methoxy-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid-Following a procedure similar to that of Example 34(D) but using 32 g. 9-benzyl-6-methoxy-1,2,15,4- tetrahydrocarbazole-4-carboxylic acid, 500 ml. of liquid ammonia and 5 g. of sodium there was obtained 7.7 g. of the title compound; M.P. 175-177 C. (tetrahydrofuranhexane). Alternatively the title compound can be prepared by substituting an equivalent amount of 9-(4-chlorobenzyl) 6 methoxy-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid for the 9-benzyl compound in this procedure.

(E) 9-benzyl 6-methoxy-l,2,3,4-tetrahydrocarbazole- 4-carboxyiic acid.Following a procedure similar to that of Example 34(E) but using 25 g. of (4-methoxyphenyl)- benzylamine, 12.5 g. ethyl 6-bromocyclohexanone-2-carboxyl-ate and 20 g. of fused powdered zinc chloride; and 20 g. of potassium hydroxide in aqueous methyl alcohol, there was obtained 9.4 g. of the title compound; M.P. 179-183" C. (isopropyl alcohol-water).

Following a procedure similar to that of Example 36(E) but substituting for (4-methoxyphenyl)-benzylamine an equivalent amount of (4-methoxyphenyl)-(4- chlorobenzyDamine there was obtained 9-(4-chlorobenzyl)-6-methoxy-1,2,3,4-tetrahydrocarbazole 4 carboxylic acid; M.P. 218220 C. (dimethylformamide-water).

Example 37 (A) 9-(4 chlorobenzoyl)-1,2,3,4-tetrahydrocarbazole- 4-carboxylic acid.Following a procedure similar to that of Example 36(A) but using 4.6 g. benzyl 9-(4-chlor0- benzoyl) 1,2,3,4-tetrahydrooarbazole 4 carboxylate in 250 ml. of ethyl acetate and 1 g. 10% palladium-oncharcoal there was obtained the title compound which, without further purification, was treated according to the procedure of Example 34(A) with 0.64 g. of 87% potassium hydroxide in 40 ml. methyl alcohol to give 3 g. of potassium 9-(4-chlorobenzoyl) 1,2,3,4 tetrahydrocarbazole-4-carboxylate; M.P. 244-247 C.

(B) Benzyl 9-(4 chlorobenzoyl) 1,2,3,4-tetrahydrocarbazo1e-4-carboxylate.Following a procedure similar to that of Example 35 (B) but using 0.8 g. sodium hydride, 90 ml. dimethylformamide, 9.15 g. of benzyl 1,2, 3,4-tetrahydrocarbazole 4 carboxylate and 5.4 g. of 4-chlorobenzoylchloride there was obtained 6.2 g. of the title compound; M.P. 123-124" C. (ethyl alcohol).

Example 38 (A) 9 (4 chlorobenzoyl) 6 methoxy-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid.Following a. procedure similar to that of Example 36(A) but using 11 g. of benzyl 9-(4-chlorobenzoyl)-6-methoxy l,2,3,4-tetrahydrocarbazole-4-carboxylate, from Example 38(B) below, in 250 ml. ethyl acetate and 1 g. of palladium-oncharcoal there was obtained 5.6 g. of the title compound; M.P. 181185 C. (ether).

(B) Benzyl 9-(4-chlorobenzoyl) 6 methoxy-1,2,3,4- tetrahydrocarbazole-4-carboxylate.Followi.ng a procedure similar to that of Example 35 (B) but using 0.85 g. sodium hydride, 50 ml. of dry dimethylformamide, 10 g. of benzyl 6-methoxy-1,2,3,4-tetrahydrocarbazole-4-carboxylate, and 5.8 g. of 4-chlorobenzoyl chloride there was obtained 11 g. of the title compound which was used without purification in the next step.

Example 39 (A) 9 benzoyl 6 methyl-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid.--Following a procedure similar to that of Example 36(A) but using 5.9 g. of benzyl 9- benzoyl-6-rnethyl-1,2,3,4-tetrahydrocarbazole 4 carboxylate in 250 ml. ethyl acetate and 1 g. of palladium-oncharcoal there was obtained 4 g. of the title compound; M.P. 149153 C. (ether-n-hexane).

(B) Benzyl 9-oenzoyl 6 methyl-l,2,3,4-tetrahydrocarbazole-4-carboxylate.Following a procedure similar to that of Example 35 (B) but using 0.84 g. sodium hydride, 50 ml. of dry dimethylformamide, 9.1 g. of henzyl 6 methyl-1,2,3,4-tetrahydrocarbazole-4-carboxylate, and 4.4 g. of benzoyl chloride, but eliminating the 1% aqueous hydrochloric acid was subsequent to the bicarbonate wash, there was obtained 8.5 g. of the title compound which was purified by suspension in hot isopropyl alcohol, filtration, followed by suspension in, and filtration from, ether; M.P. 119l2l C.

(C) Benzyl 6-methyl 1,2,3,4 tetrahydrocarbazole-4- carboxy1ate.Following a procedure similar to that of 34(C) but using 8.2 g. of 6-methyl-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid, 4.6 g. of benzyl chloride and 4 g. of sodium carbonate in 50 ml. dry dimethylform amide there was obtained 9.1 g. of the title compound; M.P. l15-ll7 C. (ethyl alcohol-pentane).

(D) 6 methyl 1,2,3,4 tetrahydrocarbazole-4-carboxylic acid.Following a procedure similar to that of Example 34(D) but using 27.5 g. of 9 benzyl-6-methyl- 1,2,3,4-tetrahydrocarbazole-4-carboxylic acid, 500 m1. of liquid ammonia and 5.9 g. of sodium there was obtained 12.2 g. of the title compound; M.P. 194-197 C. (acetonewater).

(E) 9-benzyl 6 methyl-1,2,3,4-tetrahydrocarbazole- 4-carboxylic acid-Following a procedure similar to that of Example 34(E) but using 57 g. of (4-tolyl)-benzylamine, 30 g. of ethyl 6-bromocyclohexanone-Z-carboxylate and 48 g. of fused powdered zinc chloride; and 20 g. of potassium hydroxide in aqueous ethyl alcohol, there was obtained 33 g. of the title compound; M.P. ZOO-208 C. (acetone-Water) which on recrystallization from acetone-benzene had M.P. 202-210 C.

Following a procedure similar to that of Example 31 but substituting in each case for 1-(4-toluoyl)-1-phenylhydrazine hydrochloride an equivalent amount of 1- benzoyl-l-phenylhydrazine hydrochloride and for ethyl cyclohexanone-4-carboxylate ran aquivalent amount of the following:

methyl cyclohexanone-4-carboxylate; t butyl cyclohexanone-4-carboxylate; and hexyl cyclohexanone-4-carboxylate;

there can be obtained respectively (b-l) methyl 9-benzoyl-1,2,3,4-tetrahydrocarbazole-3- carboxylate;

(b-2) t-butyl 9-benzoyl-1,2,3,4-tetrahydrocarbazole- 3-carboxylate; and

(b-3) hexyl 9-benzoyl-1,2,3,4-tetrahydrocarbazole-3- carboxylate.

The intermediate cyclohexanone-4-carboxylates above can be prepared from the corresponding free acids respectively using the standard esterification procedures disclosed hereinabove.

The title compound of Example 1(A) can alternatively be obtained from the corresponding t-butyl ester (b-2) above by pyrolysis according to the general procedure disclosed hereinabove.

Following a procedure similar to that of Example 1(B) but substituting in each case for cyclohexanone-4,4-dicarboxylic acid an equivalent amount of cyclohexanone- 4-carboxylic acid and for l-benzoyl-l-phenylhydrazine hydrochloride an equivalent amount of the hydrochlorides of the following:

1- (naphthoyl) l-phenylhydrazine;

1- 2-naphthoyl) -1-phenylhydrazine;

1-(4-chloro-1-naphthoyl)-1-(4-methoxyphenyl)hydrazine;

1- 6-bromo-2-naphthoyl) 1- (4-ohlor'ophenyl hydrazine;

1- (4-fluoro-1-naphthoyl) 1- (4-methoxyphenyl) hydrazine;

1-(4methoxy-1-naphthoyl) -1-phenylhydrazine;

1- (4-dimethylaminol-naphthoyl) l-phenylhydrazine; and

1- (4, 8-dimethoxy-3-methyl-2-naphthoyl -1-phenylhydrazine;

there can be obtained respectively (-1) 9-( l-naphthoyl) -1,2,3,4-tetrahydrocarbazole-3- carboxylic acid;

(c-2) 9-(2-naphthoyl)-1,2,3,4-tetrahydr'ocarbazole-3- carboxylic acid;

(c3) 9-(4-chloro-1-naphthoyl) -6-methoxy-1,2,3,4-

tetrahydrocanbazole-B-carboxylic acid;

(c-4) 9- (6-bromo-2-naphthoyl) -6-chloro-1,2,34-tetrahydrocarbazole-3-carboxylic acid;

(0-5) 9-(4-fluoro-1-naphthoyl)-6-methoxy-1,2,3,4-tetra hydrocarbazole-3-carboxylic acid;

(0-6) 9- (4-methoxyl-naphthoyl 1,2, 3,4-tetrahydrocarbazole-3-carboxylic acid;

(c-7) 9-(4-dimethylamino-l-naphthoyl) -l,2,3,4-tetrahydrocarbazole-3-oarboxylic acid; and

(0-8) 9- (4,8-dimethoxy-3 -methyl-2-naphthoyl 1,2, 3,4-

tetrahydrocarbazole-3-carboxylic acid.

The intermediate l-naphthoyl-l-phenylhydrazine hydrochlorides above can be prepared from the corresponding naphthoyl chlorides and phenylhydrazines respectively following the general procedures disclosed hereinabove. The naphthoyl chlorides can be obtained from the corresponding known naphthoic acids using the standard procedure disclosed hereinabove.

Alternatively the 9 naphthoyl-l,2,3,4-tetrahydrocarbazole-3-carboxylic acids above (0-1 to c-8) can be obtained by pyrolytic decarboxylation using a procedure similar to that of Example 1(A) but substituting for 9- benzoyl-l,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid an equivalent amount respectively of the following:

(cl-l) 9- l-naphthoyl) -1,2,3,4-tetrahydrocarbazole-3,3-

dicarboxylic acid;

(d2) 9- (2-naphthoyl) -1,2,3,4-tetrahydrocarbazole-3,3-

dicarboxylic acid;

(d-3) 9- (4-chlorol-naphthoyl) -6-methoxy- 1,2, 3,4-

tetrahydrocarbazole-3,3-dicarboxylic acid;

(d-4) 9- (6-bromo-2-naphthoyl) -6chloro-1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(d-S) 9- (4-fluorol -naphthoyl -6-methoxy- 1 ,2, 3,4-tetrahydrocarbazole3,3-dicarboxylic acid;

(d-6) 9- 4-methoxyl-naphthoyl) -1,2,3 ,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(d-7) 9- (4-dimethylaminol-naphthoyl 1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid; and

(d-8) 9- (4,8-dimethoxy-3-methyl-2-naphthoyl)-1,2,3,4-

tetrahydrocarbazole-3,3-dicarboxylic acid.

The above intermediate 3,3-dicarboxylic acids (d1 to d-8) can be prepared by following a procedure similar to that of Example (18) but substituting for 1 benzoyl-lphenylhydrazine hydrochloride an equivalent amount respectively of the hydrochlorides of the corresponding 1- naphthoyl-l-phenylhydrazines listed above as intermediates in the prepartion of compounds (c-1) to (c-8) Following a procedure similar to that of Example 1(B) but substituting in each case for cyclohexanone-4,4-dicarboxylic acid an equivalent amount of cyclohexanone-4-carboxylic acid and for l-benzoyl-l-phenylhydrazine hydrochloride an equivalent amount of the hydrochlorides of the following:

1-(4-trichloromethoxybenzoyl)-1-(4-t-liexylphenyl)hydrazine;

1-(4-hexyloxybenzoyl)-'1-(4-t-butylphenyl)hydrazine;

l- 4-phenoxybenzoyl) -1- (3-chloro-4-hexylthiophenyl) hydrazine;

1- (4-hexyl benzoyl 1- 3,5 -dibromophenyl hydrazine 1- (4-phenylbenzoyl) 1- (4-iodophenyl hydrazine;

1- [4- (4-phenylbutoxy) benzoyl] 1- 4- trifluoromethoxy) phenyl] hydrazine;

l- 3,5 -dibromo-4-b'utoxybenzoyl) 1- 3,4-methylenedioxyphenyl hydrazine;

l-[2-(3-phenylpropyl)benzoyl]1-phenylhydrazine;

1- [4- (Z-phenylpropyl) benzoyl] 1- (4-isopropylthiophenyl) hydrazine;

1- [4- (dimethylamino benzoyl] 1- (4-isopentyloxyphenyl) hydrazine;

l-(methylthiobenzoyl) 1- (4-benzylphenyl) hydrazine;

1- (4-isopropylthio'benzoyl) 1- (2-chloro-4-hexyloxyphenyl hydrazine;

1- (2-hexylthiobenzoyl 1- [3- S-phenylpentyl phenyl] hydrazine;

1- [4- (dibutylamino) benzoyl] 1- 3-fiuorophenyl) hydrazine;

l-lbenz0yl-1- [4- (diethy1amino)phenyl] hydrazine;

1-benzoyl- 1 [4- (dimethylamino phenyl] hydrazine;

(f-16) 9-benzoyl-6- (dimethylamino) -1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(f-17) 9-[3-(trifiuoromethoxy) benzoyl]-6-acetamido- 1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(f-l 8) 9-benzoyl-7-methoxy-6- (fi-phenylhexyloxy 1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(f-19) 9- (3-t-butylsulfinylbenzoyl- 1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(f-20) 9- (3-t-butylsulfonylbenzoyl) -8-phenyl- 1,2, 3 ,4-

tetrahydrocarbazole-3,3-dicarboxylic acid;

(f2l) 9-(4-acetamidobenzloyl)-8-phenoxy- 1,2,3 ,4-

tetrahydrocarbazole-3,3-dicarboxylic acid;

(f-22) 9-(4-butyramidobenzoyl)-6-methylthio-1,2,3,4-

tetrahydrocarbazole-3,3-dicarboxylic acid;

(f-23) 9-benzoyl-fi-methylsulfonyl-1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(f-24) 9-benzoyl-6-hexylsulfonyl-l,2,3,4-tetrahydrocarbazole-3,B-dicarboxylic acid;

(f-25) 9-benzoyl-4-isobutylsulfonyl-1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(f-26) 9-benzoyl-7-t-butylsulfinyl-1,2,3,4-tet1'ahydrocarbazole-3,3-dicarboxylic acid;

(f-27) 9-benzoyl-6-methylsu1finyl-1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(f-28 9-benzoyl-6- (trifiuoromethyl)-1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(f-29 9-benzoy1-6- (trichloromethyl -1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(f30) 9-(4-benzyloxybenzoy1)-l,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(f-3 1 9- (4-nitrobenzoyl l,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid; and

(f-32) 9-benzoyl-6-nitro-l,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid.

The above intermediates 3,3-dicarboxylic acids (f-l to f-32) can be prepared by following a procedure similar to that of Example 1(B) but substituting for l-benzoyllphenylhydrazine hydrochloride an equivalent amount re spectively of the hydrochlorides of the corresponding 1-benzoyll-phenylhydrazines listed above as intermediates for the preparation of compounds (e-l) to (e32) inclusive. The intermediate l-benzoyl-l-phenylhydrazine hydrochlorides listed above can be prepared from the corresponding benzoyl chlorides and corresponding phenylhydrazine using the general procedure disclosed hereinabove. The intermediate benzoyl chlorides and intermediate phenylhydrazines, listed above as intermediates in the preparation of compounds (e-l) to (e40) inclusive, are known compounds or can be prepared from the corresponding known benzoic acids and corresponding known anilines respectively using the general procedures disclosed hereinabove.

By using the general procedure described hereinbefore for the hydrogenation of benzyloxy and nitro substituents to hydroxy and amino substituents respectively there can be obtained from 9-benzoyl-6-benzyloxy-l,2,3,4-tetrahydrocarbazole-3-carboxylic acid (Example 30), componnds (e-30) to (e-32) inclusive above, 9-benzoyl-6-benzyloxy- 1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid (a22) and compounds (f-30) to (f-32) inclusive above respectively the following:

(g-l) 9-benzoyl-6-hydroxy-1,2,3,4-tetrahydrocarbazole-3-carboxylic acid;

(g-2) 9- (4-hydroxybenzoyl) -1,2,3,4-tetrahydrocarbazole-3-carboxylic acid;

(g-3) 9- (4-aminobenzoyl) -1,2,3,4-tetrahydrocarbazole-3-carboxylic acid;

(g-4) 9-benzoyl-6-amino-1,2,3,4-tetrahydrocarbazole-B-carboxylic acid;

(g-S 9-benzoyl-6-hydroxy-1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

(g-6) 9-(4-hydroxybenzoyl)-1,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

28 (g-7) 9-(4-aminobenzoyl)-l,2,3,4-tetrahydrocarbazole-3,3-dicarboxylic acid; and (g-8) 9-benzoyl-6-amino-1,2, 3 ,4-tetrahydrocarbazole-3,3-dicarboxylic acid;

The 3,3-dicarboxylic acids above (g-S to g-8) can be converted to the corresponding 3-carboxylic acids ((g-l) to (g-4) above)) by pyrolytic decarboxylation according to a procedure similar to that of Example 1(A).

Alternatively, as described hereinabove, the 9-benzoyl- 1,2,3,4-tetrahydrocarbazole-3-carboxylic acids can be prepared from their corresponding benzyl esters. Thus, by following a procedure similar to that of Example 34(A) but substituting for benzyl 9-benzoyl-l,2,3,4-tetrahydrocarbazole-4-carboxylate an equivalent amount of the following:

(h l) benzyl 9-benzoy1-8-phenyl-1,2,3,4-tetrahydrocarbazole-3-carboxylate; and

(h-2) benzyl 9-benzoyl-6-benzyloxy-1,2,3,4-tetrahydrocarbazole-3-carboxylate there can be obtained respectively (i1) 9-benzoyl-8-phenyl-1,2,3,4-tetrahydrocarbazole- 3-carboxylic acid; and

(i-2) 9-benzoyl-6-hydroxy-1,2,3,4-tetrahydrocarbazole- B-carboxylic acid.

The intermediate benzyl esters (h1) and (h-2) above can be prepared by following a procedure similar to that of Example 35(3) but substituting in each case for 4-toluoyl chloride an equivalent amount of benzoyl chloride and for benzyl 1,2,3,4tetrahydrocarbazole-4-carboxylate an equivalent amount respectively of the following:

(j-1) benzyl 8-phenyl-1,2,3,4-tetrahydrocarbazole-3- carboxylate; and

(i -2) benzyl 6-benzyloxy-1,2,3,4-tetrahydrocarbazole- 3-carboxylate.

The intermediate benzyl esters (j1) and (j-2) above can be prepared following a procedure similar to that of Example 34(C) but substituting for 1,2,3,4-tetrahydrocarbazole-4carboxylic acid an equivalent amount respectively of the following:

(k1) 8-phenyl-1,2,3,4-tetrahydrocarbazole 3 carboxylic acid; and

(k-Z) 6-benzyloxy-l,2,3,4-tetrahydrocarbazole 3 carboxylic acid.

The above 3-carboxylic acids (k-l) [M.P. 2l9-222 C. (ethyl acetatehexane)] and (k-2) [M.P. 216-218 C. (acetone-Water)] were obtained by following a proce dure similar to that of Example 1(B) but substituting in each case for cyclohexanone-4,4-dicarboxylic acid an equivalent amount of cyclohexanone-4-carboxylic acid and for l-benzoyl-l-phenylhydrazine hydrochloride an equivalent amount respectively of the hydrochlorides of the following:

2-biphenylhydrazine; and 4-benzyloxyphenylhydrazine.

S-phenyl-l,2,3,4-tetrahydrocarbazole 3-carboxylic acid (k1) was found to be active when tested in rats at mg./kg. of body weight in the Inhibition of Carrageenin- Induced Foot Edema and Adjuvant-Induced Arthritis Test Procedures described hereinbefore and is indicated for use as an antiinflammatory agent.

In a like manner, by following a procedure similar to that of Example 34(A), there can be obtained from the benzyl esters (l-l) to (l) inclusive below the corresponding 9-aroyl-1,2,3,4-tetrahydrocarbazole 3 carboxylic acids of Examples 1(A) to 8(A) inclusive, Examples 9 to 29 inclusive, (c-l) to (c8) inclusive, (e-l) to 33 (n-3 l 6- 3,5-dichloro-4-methoxyphenyl) l,2,3,4-tetrahydrocarbazole-3-carboxylic acid; (n-32) 6-(4-t-butylphenyl)-1,2,3,4-tetrahydrocarbazole- 3-carboxylic acid; and (n-33) 6- [3-(trifluoromethyl) phenyl] -1,2,3,4-tetrahydrocarbazole-3-carboxylic acid.

The intermediate 1,2,3,4-tetrahydrocarbazole-3-carboxylic acids (n-l to n-33 above) can be obtained by following a procedure similar to that of Example 1(B) but using equivalent amounts of the appropriate phenylhydrazine hydrochloride and, in each case, cyclohexanone- 4-carboxylic acid.

Following a procedure similar to that described in Example l(B) but substituting for cycloheXanone-4,4-dicarboxylic acid an equivalent amount of 4-methylcyclohexanone-4-carboxylic acid there can be obtained 9-benzoyl-3-methyl-1,2,3,4-tetrahydrocarbazole- 3-carboxylic acid.

Following a procedure similar to that of Example 34A but substituting for benzyl 9-benzoyl-l,2,3,4-tetrahydrocarbazole-4-carboxylate an equivalent amount of the following there can be obtained respectively (p-l 9- l-naphthoyl l,2,3,4-tetrahydrocarbazole-4- carboxylic acid;

(p 2) 9-(Z-naphthoyl)-l,2,3,4-tetrahydrocarbazole-4- carboxylic acid;

(p-3) 9-(4-chloro-l-naphthoyl)-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid;

(p-4) 9- (6-bromo-2-naphthoyl) -1,2,3,4-tetrahydrcarbazole-4-carboxylic acid;

(p-S) 9-(4-fluoro-l-naphthoyl)-l,2,3,4-tetrahydrocarbazole-4-carboxylic acid;

(p-6) 9-(4-methoxy-l-naphthoyl)-l,2,3,4-tetrahydrocarbazole-4-carboxylio acid;

(p-7) 9-(4-dimethylamino-l-naphthoyl)-l,2,3,4- tetrahydrocarbazole-4-carboxylic acid; and

(p-8) 9- (4, 8-dimethoxy-3-methyl-2-naphthoyl 1,2,3,4-tetrahydrocarbazole-4-carboxylic acid.

The intermediate benzyl 9-naphthoyl-1,2,3,4-tetrahydro carbazole-4-carboxylatts (0-1 to 0-8 above) can be prepared by following a procedure similar to that of Example 35( B) but substituting respectively for 4-toluoyl chloride an equivalent amount of the following:

l-naphthoyl chloride;

Z-naphthoyl chloride;

4-chloro-l-naphthoyl chloride; 6-bromo-2-naphthoyl chloride; 4-fiuoro-1-naphthoy1 chloride; 4-methoXy-l-naphthoyl chloride; 4-dimethylamino-l-naphthoyl chloride; and 4,8-dimethoxy-3-methyl-2-naphthoyl chloride.

The naphthoyl chlorides listed above can be prepared from the corresponding known naphthoic acids according to the general procedures disclosed hereinabove.

Following a procedure similar to that of Example 35 (B) but substituting in each case for 4-toluoyl chloride an equivalent amount of benzoyl chloride and for benzyl- 1,2,3,4-tetrahydrocarbazole-4-carboxylate an equivalent amount of the following:

methyl l,2,3,4-tetrahydrocarbazole-4-carboxylate; t-butyl-l,2,3,4-tetrahydrocarbazole-4-carboxylate; and hexyl 1,2,3,4-tetrahydrocarbazole-4-carboxylate;

there can be obtained respectively (q-l) methyl 9-benzoyl-1,2,3,4-tetrahydrocarbazole-4- carboxylate;

(q-2) t-butyl 9-benzoyl-1,2,3,4-tetrahydrocarbazole-4- carboxylate; and

(q-3) hexyl 9-benzoyl-1,2,3,4-tetrahydrocarbazole-4- carboxylate.

The intermediate methyl, t-butyl and hexyl esters of 1,2,3,4-tetrahydrocarbazole-4-carboxylic acid can be prepared from the corresponding free acid using the known esterification procedures disclosed hereinabove.

The title compound of Example 34(A) can alternatively be obtained from t-butyl 9-benzoyl-l,2,3,4-tetrahydrocarbazole-4-carboxylate (q-2) by pyrolysis according to the general procedure disclosed hereinabove.

Following a procedure similar to that of Example 34(A) but substituting for benzyl 9-benzoyl-1,2,3,4-tetrahydrocarbazole-4-carboxylate an equivalent amount of the following:

(r-l) 2,4-difluorobenzyl 9- (4-chlorobenzoyl)-6-fluoro- 1,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-2) 4-iodobenzyl 9-(4-trichloromethoxybenzoyl)-6- hexyl-l,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-3) 4-chlorobenzyl 9-(4-hexyloxybenzoyl)-6-t-butyl- 1,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-4) 4-bromobenzyl 9-(4-phenoxybenzoyl)-7-chloro-6- hexylthio-l,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-5) 4-ethylbenzyl 9-(4-hexylbenzoyl)-5,7-dibromo- 1,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-6) 4-(1,3-dimethylbutyl)benzyl 9-(4-phenylbenzoyl)- 6-iodo-1,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-7) 3,4-methylenedioxybenzyl 9-[4-(4-phenylbutoxy)- benzoyl]-6-(trifluoromethoxy)-1,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-8) 4-isopropoxybenzyl 9-(3,5-dibromo-4-butoxybenzoyl) -6,7-methylenedioxy- 1 ,2, 3,4-tetrahydrocarbazole-4-carboxylate;

(r-9) 3,4,5-trimethoxybenzyl 9-[2-(3-phenylpropyl) benzoyl]-6-methyl-l,2,3,4-tetrahydrocarbazole-4- carboxylate;

(r-lO) 3,4-dipropoxybenzyl[4-(2-phenylpropyl) benzoyl]-6-isopropylthio-l,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-1 1) 4-methoxy-3,S-dimethylbenzyl 9- [4- (dimethylamino)-benzoyl]-6-isopentyloxy-1,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-12) benzyl 9-(4-methylthiobenzoyl)-6-benzyl-l,2,3,4-

tetrahydrocarbazole-4-earboxylate;

(r-l3) benzyl 9-(4-isopropylthiobenzoyl)-8-chloro-6- hexyloxy-l,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-l4) benzyl 9- (2-hexylthiobenzoyl)-5-(5-phenylpentyl) -1,2,3 ,4-tetrahydrocarbazole-4-carb oxyl ate (r-15) benzyl 9-[4-(dibutylamino)benzoyl]-5-fluoro- 1,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-l6) benzyl 9-(4-t-butylbenzoyl)-6-(diethylamino)- l.2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-17) benzyl 9-(4-methoxybenzoyl)6-(dimethylamino)-1,2.3-4-tetrahydr0carbazole-4-carboxylate;

(r-18) benzyl 9-[B-(trifiuoromethoxy)benzoyl]-l,2,3,4-

tetrahydrocarbazole-4-carboxylate;

(r-19) benzyl 9-benzoyl-7-methoxy-6-(6-phenylhexyloxy)-l,2,3,4-tetrahydrocarbazole-4-carboxylate;

(r-20) benzyl 9-(4-fiuorobenzoyl)-8-phenyl-l,2,3,4-

tetrahydrocarbazole-4-carboxylate;

37 which in turn can be hydrogenated according to the procedure disclosed hereinabove to give 9-(4-hydroxybenzoyl)-1,2,3,4-tetrahydrocarbazole- 4-carboxylic acid (s-26 above).

The intermediate t-butyl-l,2,3,4-tetrahydrocarbazole-4- carboxylate (u-l) can be obtained from the corresponding free carboxylic acid using the known esterificatiou procedure disclosed hereinabove.

Following a procedure similar to that of Example 35(B) but substituting for benzyl 1,2,3,4-tetrahydrocarbazole-4-carboxylate and for 4-toluoyl chloride equivalent amounts of t-butyl 6-benzyloxy-1,2,3,4-tetrahydrocarbazole-4-carboxylate and benzoyl chloride respectively there can be obtained (v-1) t-butyl 9-benzoyl-6-benzyloxy-l,2,3,4-tetrahydrocarbazole-4-carboxylate,

which can be pyrolized, using the general procedure disclosed hereinabove, to give (v-2) 9-benzoyl-6-benzyloxy-l,2,3,4-tetrahydrocarbazole-4-carboxylic acid,

which in turn can be hydrogenated according to the procedure disclosed hereinabove to give (v-3) 9-benzoy1-6-hydroxy-1,2,3,4-tetrahydrocarbazole- 4-carboxylic acid.

The intermediate t-butyI-G-benzyloxy-l,2,3,4-tetrahydrocarbazole-4-carboxylate can be obtained from 6-benzyloxy-l,2,3,4-tetrahydrocarbazole-4-carboxylic acid using known esterification procedure disclosed hereinabove. The latter compound can be obtained by following procedures similar to those of Examples 34(E) and 34(D) but substituting for phenylbenzylamine an equivalent amount of 4-benzyloxyphenylbenzylamine for 9-benzyl- 1,2,3,4-tetrahydrocarbazole-4-carb0xylic acid an equivalent amount of 9-benzyl-6-benzyloxy-1,2,3,4-tetrahydrocarbazole-4-carboxylic acid respectively.

Following a procedure similar to that of Example 34(A) but substituting for benzyl 9-benzoyl-l,2,3,4-tetrahydrocarbazole-4-carboxylate an equivalent amount of the following:

(w-l) benzyl 9-benzoyl-4-methyl-l,2,3,4-tetrahydrocarbazole-4-carboxylate;

(w-2) benzyl 9-benzoyl-3-methyl-1,2,3,4-tetrahydrocarbazole-4-carboxylate;

(w-3) benzyl 9-benzoyl-2-methyl-1,2,3,4-tetrahydrocarbazole-4-carboxy1ate; and

(w-4) benzyl 9-benzoyl-l-methyl-1,2,3,4-tetrahydrocarbazole-4-carboxylate;

there can be obtained respectively (x-l) 9-benzoyl-4-methyl-1,2,3,4-tetrahydrocarbazole- 4-carboxylic acid;

(x-2) 9-benzoyl-3-methyl-1,2,3,4-tetrahydrocarbazole- 4-carboxylic acid;

(x-3) 9-benzoyl-2-methyl-1,2,3,4-tetrahydr0carbazole- 4-carboxylic acid; and

(x-4) 9-benzoyl-1-methy1-1,2,3,4-tetrahydrocarbazole- 4-carboxylic acid.

The intermediate benzyl 9-benzoyl-methyl-1,2,3,4-tetrahydrocarbazole-4-carboxylates (w-l to w-4 above) can be obtained by following in sequence procedures similar to those of Examples 34(F) to 34(B) inclusive but substituting respectively in Example 34(F) for ethyl cyclohexanone-Z-carboxylate an equivalent amount of the following:

ethyl Z-methylcyclohexanone-Z-carboxylate; ethyl 3-methylcyclohexanone-2-carboxylate; ethyl 4-methylcyclohexanone-2-carboxylate; and ethyl -methylcyclohexanone-2-carboxylate;

and using in Examples 34(E) to 34(B) inclusive equivalent amounts of the corresponding ethyl 6-bromocyclo- 38 hexanone-Z-carboxylates, 9-benzyl l,2,3,4 tetrahydrocarbazole-4-carboxylic acids, l,2,3,4-tetrahydrocarbazole- 4-carboxylic acids and benzyl 1,2,3,4-tetrahydrocarbazole- 4-carboxylates respectively.

Example 40 9-benzoyl-6-hydroxy 1,2,3,4 tetrahydrocarbazole-3- carboxylic acid.A solution of 8.1 g. of 9-benzoyl-6- benzoyloxy 1,2,3,4 tetrahydrocarbazole-3-carboxylic acid in 250 ml. of ethyl acetate over 1.5 g. of 10 percent palladium-on-charcoal was subjected to a hydrogen atmosphere at about 40 p.s.i.g. while being heated with a heat lamp. The reaction was stopped when a theoretical amount of hydrogen had been adsorbed (one hour) and the resulting cooled mixture was filtered and evaporated to dryness under reduced pressure. The residue was crystallized from acetone-n-hexane to yield 4.1 g. of the title compound; M.P. 224-227 C.

Example 41 9 (3 fluorobenzoyl) 1,2,3,4 tetrahydrocarbazole- 3-carboxylic acid-Following a procedure similar to that of Example 1(B) but using 8.7 g. of l-(3-fluorobenzoyl)- l-phenylhydrazine hydrochloride and 5.0 g. of cyclohexanone-4-carboxylic acid there was obtained 9.2 g. of the title compound; M.P. -171 C.

Example 42 9 (4 phenylbenzoyl) 1,2,3,4 tetrahydrocarbazole- 3-carboxylic acid.Following a procedure similar to that of Example 1(B) but using 13.5 g. of 1-(4-phenylbenzoyl)-l-phenylhydrazine hydrochloride and 6.86 g. of cyclohexanone-4-carboxylic acid there was obtained 12 g. of the title compound; M.P. 212-213 C. (acetone-water).

Example 43 9 benzoyl 8 fiuoro l,2,3,4 tetrahydrocarhazole- 3-carboxylic acid.A solution of 6.4 g. benzaldehyde 1- benzoyl-1-(2-fluorophenyl)hydrazone and 5.35 g. of cyclohexanone-4-carboxylic acid in 50 ml. glacial acetic acid and 10 ml. of glacial acetic acid saturated with hydrogen chloride was heated under reflux for two hours. An additional 10 ml. glacial acetic acid saturated with hydrogen chloride was then added and heating under reflux was continued two additional hours. A further 5 ml. glacial acetic acid saturated with hydrogen chloride was added and heating under reflux was continued another two hours. The mixture was cooled, 25 ml. water was added portion-wise, and the resulting solid was collected by filtration and Washed with water to yield 3.54 g. of the title compound; M.P. 250-251 C. (acetic acid-water).

The benzaldehyde l-benzoyl-l-(2-fiuor0phenyl)hydrazone was prepared as follows: A stirred solution of 2.1 g. of benzaldehyde (2-fiuorophenyl)hydrazone in 40 ml. dry dimethylformamide was treated with 0.23 g. sodium hydride in a nitrogen atmosphere with water-bath cooling. When hydrogen evolution had ceased, there was added dropwise a solution of 1.2 ml. of benzoyl chloride in a small amount of dry dimethylformamide and stirring was continued for three hours. To this mixture was added enough glacial acetic acid to neutralize any excess alkali, water, and ether. The ether extract was washed with water several times, dried, and evaporated to dryness under reduced pressure to yield 1.7 g. of benzaldehyde l-benzoyll-(2-fluorophenyl)hydrazone; M.P. 9799 C. (ethyl alcohol-water).

Example 44 9 benzoyl 8 bromo 1,2,3,4 tetrahydrocarbazole- 3-carboxylic acid.A solution of acetaldehyde l-benzoyl- 1-(Z-bromophenyl)hydrazone, prepared from 11 g. of acetaldehyde Z-bromophenyl hydrazone (see below), and 9.16 g. of cyclohexanone-4-carboxylic acid in 25 ml. glacial acetic acid was heated on a hot plate until evolution of acetaldehyde was no longer detected (about two hours), 25 ml. glacial acetic acid saturated with hydrogen chloride was added and heating was continued for 30 minutes. The mixture was cooled and cautiously diluted wtih water, and the resulting solid was collected by filtration and washed with water to give 2.24 g. of the title compound; M.P. 196-198" C. (chloroform-heptane).

The acetaldehyde l-benzoyl-1-(2-bromophenyl)hydrazone was prepared as follows: A solution of 11.2 g. of 2-bromophenyl hydrazine in ether was treated with 7 ml. of acetaldehyde and allowed to stand for one hour with occasional swirling. The ether solution was washed with water, a small amount of dilute potassium bicarbonate solution, and saturated sodium chloride solution, dried over magnesium sulfate and evaporated to dryness under reduced pressure. The residue was taken up in 25 ml. dry dimethylformamide and the resulting solution was added dropwise, with stirring and water-bath cooling, to a mixture of 1.56 g. of sodium hydride in 25 ml. dry dimethylformamide and stirring was continued for one hour. To this solution under nitrogen was added dropwise with stirring a solution of 7 ml. of benzoyl chloride in 10 ml. of dimethylformamide and stirring was continued for four hours. The mixture was diluted with ether and treated with water containing sufiicient glacial acetic acid to neutralize excess alkali. The ether extract was washed with water, dilute potassium carbonate solution, water, and saturated sodium chloride solution, dried over magnesium sulfate and evaporated to dryness under reduced pressure to give acetaldehyde l-benzoyl-l-(Z-bromophenyl)hydrazone which was used as such in the above reaction.

Example 45 Pivaloyloxymethyl 9 benzoyl-1,2,3,4-tetrahydrocarbazole-3-carboxylate.-A mixture of 12.8 g. of '9-benzoyl- 1,2,3,4-tetrahydrocarbazole-3-carboxylic acid, 20 g. of potassium bicarbonate, 12 ml. of chloromethyl pivalate in 50 ml. of dry dimethylformamide was stirred and heated on a steambath for two hours. The mixture was cooled and diluted with ether, the ether mixture was washed several times with water, dried over magnesium sulfate, and evaporated under reduced pressure to dryness to give 10.6 g. of the title compound; M.P. 75-77 C. (methyl alcohol).

Example 46 lBenzoyloxymethyl 9 benzoyl-l,2,3,4-tetrahydrocarbazole-3-carboxylate. Following the procedure similar to that of Example 45 but using 12.8 of 9 benzoyl-1,2,33,4- tetrahydrocarbazole-3-carboxylic acid, 20 g. of potassium bicarbonate, ml. of chloromethyl benzoate in 50 ml. of dry dimethylformamide there was obtained, after filtration of the ether extract through silica gel followed by combination of those fractions showing only one identical spot on thin layer chromotography and evaporation to dryness under reduced pressure, 14 g. of the title compound; M.P. 84-86 C. (methyl alcohol).

Example 47 4-acetamidopheny1 9-benzoyl 1,2,3,4 tetrahydrocarbazole 3 carboxylate-A solution of 9.6 g. of 9- benzoyl 1,2,3,4 tetrahydrocarbazole 3 carboxylic acid, ml. of thionyl chloride and two drops of dry dimethylformamide in 100 ml. of ethylene dichloride was stirred at room temperature for seven hours. The mixture was evaporated to dryness under reduced pressure, at room temperature, and to the resulting residue was added a solution of 6 g. of 4-acetamidophenol in 50 ml. of dry pyridine. The solution was stirred at room temperature for 30 minutes and diluted with water. The resulting solid was collected by filtration to give 6.74 g. of the title compound; M.P. 166-168 C. (ethyl alcohol).

Following procedures similar to that of Examples 45, 46 and 47 but substituting in each case for 9-benzoy1- 1,2,3,4 tetrahydrocarbazole 3 carboxylic acid an equivalent amount of 9-benzoyl 1,2,3,4 tetrahydrocarbazole 4 carboxylic acid there are obtained respectively:

(y-l) pivaloyloxymethyl 9-benzoyl-1,2,3,4-tetrahydrocarbazole-4-carboxylate;

(y-2) benzoyloxymethyl 9-benzoy1-1,2,3,4-tetrahydrocarbazole-4-carboxylate; and

(y-3) 4-acetamidophenyl 9-benzoyl-1,2,3,4-tetrahydrocarbazole-4-carboxylate.

Following a procedure similar to that of Example 45 but substituting for chloromethyl pivalate an equivalent amount of chloromethyl 3- (trifluoromethyl) benzoate; chloromethyl 4-t-butylbenzoate; chloromethyl 4-toluate;

chloromethyl 4-fluorobenzoate; chloromethyl 3-anisoate;

chloromethyl 4-ethoxy-3-fluorobenzoate; chloromethyl 2,4-dichlorobenzoate; chloromethyl 4-nitrobenzoate; and chloromethyl 4-trifluoromethoxybenzoate there can be obtained respectively:

(z-l) 3-(trifluoromethyl) benzoyloxymethyl 9-benzoyl- 1,2,3,4-tetrahydrocarbazole-3-carboxylate;

(z-2) 4-t-butylbenzoyloxymethyl 9-benzoyl-1,2,3,4-

tetrahydrocarbazole-3-carboxylate;

(z-3) 4-toluoyloxymethyl 9-benzoyl-l,2,3,4-

tetrahydrocarbazole-3-carboxylate;

(z-4) 4-fluorobenzoyloxymethyl 9-benzoyl-1,2,3,4-

tetrahydrocarbazole-3-carboxylate;

(z-S) 3-anisoyloxymethyl 9-benzoyl-1,2,3,4-

tetrahydrocarbazole-3-carboxylate;

(z-6) 4-ethoxy-3-fluorobenzoyloxymethyl 9-benzoyl- 1,2,3,4-tetrahydrocarbazol -3-carboxy1ate;

(z-7) 2,4-dichlorobenzoyloxymethyl 9-benzoyl- 1,2,3,4-tetrahydrocarbazole-3-carboxylate;

(z-8) 4-nitrobenzoyloxymethyl 9-benzoyl-1,2,3,4-

tetrahydrocarbazole-3-carboxlylate;

(z-9) 4-trifluoromethoxybenzoyloxymethyl 9-benzoyl- 1,2,3,4-tetrahydrocarbazole-3-carboxylate;

Example 48 9-benzoyl 3 hydroxymethyl l,2,3,4 tetrahydrocarbazole.1-benzoyl 1 phenylhydrazine hydrochloride (23.8 g.) and 18 g. of 4-hydroxymethylcyclohexanone ethylene ketal in 450 ml. of absolute ethyl alcohol was heated under reflux for four hours. The chilled mixture was filtered, the filtrate was evaporated to dryness under reduced pressure and the resulting residue was dissolved in ether. The ether solution was washed with water, dilute hydrochloric acid, water, dilute sodium bicarbonate, and water, dried and evaporated to dryness to give, after recrystallization from ethyl acetate-hexane, 9.6 g. of 9- benzoyl 3 hydroxymethyl 1,2,3,4 tetrahydrocarbazole; M.P. 105-107 C.

Preparation of 4-hydroxymethylcyclohexanone ethylene ketal.--Ethyl cyclohexanone 4 carboxylate (335 g.), 550 ml. ethylene glycol and 21 g. of p-toluenesulfonic acid in 5.5 liters of benzene were heated at reflux with stirring for twenty-four hours while water Was separated by means of a water trap. The mixture was cooled and poured into 4 liters of ice water. The benzene layer was separated, washed with 1 liter of 5% sodium bicarbonate, 1 liter of water and 1 liter of saturated sodium chloride solution, dried and evaporated to dryness to give, after distillation, 245.6 g. of ethyl cyclohexanone- 4-car-boxylate ethylene ketal; B.P. 99.5 C. (0.07 mm.); N 1.4620. A solution of 35 g. of the ketal-ester in 50 m1. of dry tetrahydrofuran was added dropwise to 5.7 g. of lithium aluminum hydride in 250 ml. of dry tetrahydrofuran, and the mixture was heated at reflux for five hours and cooled to room temperature. A saturated sodium chloride solution (11.4 ml.) was added 

